Transplant consultation

F Body General Discussion

  1. old yellow 78

    old yellow 78 Well-Known Member

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    What would be involved in swapping out the Super Six in OY with a Magnum 318 or perhaps a 360?
    - Would it need a new K member, or are there mounts that could be adapted?
    - Could I use the existing wiring system, or would it have to be modified or replaced?
    - Could I still use the A833 "overdrive" four speed?
    - Would the suspension have to be modified?
    - What other problems/challenges would this switch involve?
    - Keeping in mind that I am not a mechanic, I would have to have this done. What could I reasonably expect to pay for the engine and the work to have it installed?
    - What engine (318, 360, 318 Magnum) would be the best engine to use for this?
    - Should I just leave well enough alone?

    I am basically satisfied with the Super Six that is in OY, and I'm not interested in making a "hot rod" out of it, BUT I have often thought that I would like to have more power. So, I thought I would find out just what would be involved if I ever did decided to switch things out. :confused:
     
  2. Oldiron440

    Oldiron440 Well-Known Member

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    I the if I were to pick one from your list of three it would be a magnum motor. The only thing you will need is a Abody oil pan and pick up and bellhousing a carb and intake. When picking the block you might want to look at the motor mount location the block, some had both front and center but later ones only had center.
     
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  3. Magnum Aspen

    Magnum Aspen Member

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    Check magnumswap.com, lots of good information.
    You will also need to consider the front end accessory drive, wiring, radiator.
    engine-swaps.com, Schumacher creative services, sells engine mounts that are advertised to allow putting a small block into a S6 K frame.
    I purchased fire wall gaskets from Schumacher creative services and was totally satified.
     
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  4. F body Deconstructor Jim

    F body Deconstructor Jim Well-Known Member

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    use existing K with schumacher mounts. they work excellent and leave more room than a V8 K.

    existing wiring can be modified...unwrapped, wires moved, rewrapped.

    A833 yes but you'll need the V8 OD bellhousing and maybe Z bar.

    no suspension mods req'd. Hooray!

    you'll need a radiator, accessory brackets, etc. (a different ps pump bracket too:D)

    no clue on what it would cost.
    labor alone would have to be a grand though...
    I did mine in a long weekend solo but I had everything lined up and ready to go.

    If your super is running as it should I'd leave it alone.
    My 225-1 was getting tired and noisy.
    Plus I had this sweet low mile roller lifter 360 sitting there, just begging me to use it....:rolleyes::D

    IMG_20180613_154239368_HDR.jpg
     
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  5. Oldiron440

    Oldiron440 Well-Known Member

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    Good point on the Z bar, on a Abody there is a difference between the /6 and V8 Z bar leverages and it's not recommended to modify the /6 bar. I would think the same thing would apply with the Fbody.
     
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  6. Darth-Car

    Darth-Car Well-Known Member

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    Really there is not a lot of difference in performance from a standard 318, and a super 6. I would change the gearing in the rear if you wanted some additional getty-up, and leave all of the complicated swap stuff in the front alone.
     
  7. AJ/FormS

    AJ/FormS Well-Known Member

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    I agree with Darth.
    That od-box already has a 3.09 low in it,and a .73overdrive. (3.09-1.67-1.00-.73od)
    All you gotta do is marry that to the right rear gear for your use and driving style, and get the exhaust out of that head; and yur away.
    To cruise at 65=2200, you could run 3.73s, and that would get you a starter gear of 11.53, which is quite a bit. So taking off will be a breeze.
    The problem comes when you get into second gear. The Rs fall to 54%, so you gotta rev first out pretty good, if you want to pull hard in second.

    Here's how they stack up. Lines 1 and 2 are autos and I grossed them up 5% to allow for the TC, just to make it a fair comparison. the asterisk denotes in loc-up
    1) A998/3.55; - 9.13-5.40-3.73-3.55; 65=2870*
    2) A999/3.23; - 9.29-5.22-3.39-3.23; 65=2740*
    3) A833/3.23; - 9.98-5.39-3.23-2.36; 65=1900
    4) A833/3.73; 11.52-6.23-3.73-2.72; 65=2200
    5) A833/4.10; 12.67-6.85-4.10-2.99; 65=2420
    6) Commando/3.55; 10.97-6.82-4.97-3.55; cruizes at 55=2430
    7) Commando/3.23;- 9.98-6.20-4.52-3.23; cruizes at 60=2410
    Notice that the first three all have about the same second gear ratios. They're all gonna pull about the same, in the first two gears.
    But look at the fourth line; first gear is 25% bigger/ second is 17% bigger/ and third doesn't really matter cuz now yur getting up in speed, and mostly cruising.
    What those number mean is the bigger they are in each gear, the more powerful your slanty will feel in that gear.
    But look at the cruising rpm!
    If you wanted to you could run even more rear gear. But there will come a point that first gear feels just too low. That comes at around 13.29 with 4.30s,and the cruise goes up to 2530rpm
    But check out the 4.10s, and compare that to the A999; plus 36% in first, plus 31% in second, and passing gear is plus 21% yet the cruise rpm is down 12% or 320rpm.
    Yur gonna need a LSD with the 4.10s,lol.

    So how would that compare to a 5.2Magnum?
    IDK but here's a guess.
    Say that 5.2 makes 240ftlbs at 1800, and the car currently has 2.76s in it . Lets do second gear only. Ok then;
    240x1.67x2.76= 1106 ftlbs@31 mph into the axles

    Next; say the slanty can muster 120ftlbs@1800 (I'm really guessing), and the 4.10/A 833 combo; and I get;
    120x1.67x4.10=822 ft lbs, at 21mph. But by the time you get to 31 mph, the rpm will be 2640 and the torque will gave climbed to near peak, and I'll guess 161 ftlbs, lol, so the torque into the rear axles would be 161x1.67x4.10=1102ftlbs@31mph. Ok I'll admit it; I might have fudged the numbers to prove the point; but if I did, it wasn't by much.

    But, this match-up only occurs up to 31mph or so. As the speed increases the Magnum is gonna climb up the torque curve, while the slanty is soon gonna be sliding down it's curve.

    Let's try passing-gear at 55mph; the Magnum in second gear,will be at ~3700, probably a bit past peak torque say 300 ft lbs(guessing again) so I get
    300x1.67x2.76=1383 on-road ftlbs@55 mph. BTW; 300ftlbs@3700 is 211hp

    And the slanty will be at 4700 in second, too high. So lets try third (direct) and I get 2810 rpm; so again close to peak torque. So lets call it 200 ftlbs, and I get
    200x1.00x4.10=820 on-road ftlbs@55mph. BTW; 200ftlbs @2810rpm is 107hp
    So, against the Magnum it is clearly a loser.
    But let's compare it to itself with 2.76s. 55 will be 3150, sliding down the torque-curve now, so lets call it 190 ftlbs, and I get;
    190x1.67x2.76=876 on-road ftlbs @55 mph.
    Huh; 2.76s suck :(
    And so does trying to pass in direct gear, even with 4.10z,lol. :(

    My torque numbers may not be accurate, but as you can see the point is made even so.
    So, altho I agree with Darth;
    with a stock slanty you just can't expect miracles after 30 mph. However, for the buy-in, it ain't too bad. And you don't have to be a mechanic to swap a complete rear end. And if you pay a guy to install new gears, it's still is pretty do-able.

    As for the Magnum swap;
    Yur also gonna need mounts,a bellhouse/etc, and a new exhaust system, and I would recommend bigger T-bars. And I guess an intake and carb, plus fudging with the serpentine system, maybe some hoses and a fuel pump, and, on and on.
    And don't forget;
    if the crank is not drilled for the trans input shaft,then you gotta deal with that too.
    And the serpentine waterpump turns backwards. So if you eliminate that stuff, you also get to buy a new pump and front cover.

    Parting shot; if this is mostly a city car only; then the 3.09Commando box and 3.55s is awesome;
    6) A833/3.55; 10.97-6.82-4.97-3.55; cruizes 55=2430rpm
    Now you got a passing gear; 55will be 3400rpm in third, again sliding down the torque curve but now you horsepower on your side and that 4.97 gear is wickedly fast.
    In fact; if you already have 3.23s(or better); that Commando box is hard to beat.
    7) Commando/3.23; 9.98-6.20-4.52-3.23; cruizes at 65=2600
    and passing gear is 3100 so just a tic over peak torque.

    The buy-in for a Commando box is likely a lil less than the rear-end deal; plus it's a straight swap in. On a 4-post hoist I've taken mine down in 17 minutes; including the GVod and the front exhaust.

    As always; Happy HotRodding
     
    Last edited: Oct 30, 2019
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  8. AJ/FormS

    AJ/FormS Well-Known Member

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    They say the slanty has a hard time getting rid of exhaust, and there is a guy in the slanty forum (maybe lotsa guys, IDK); who did some mods to his engine, but until he split the manifold and installed duals, it was rather disappointing for him. After the split he got a lil excited,lol.
    And I would have to agree with that. I pumped mine up to 9.5Scr with a very small solid cam, and the SuperSix transplant. But it wasn't any quicker that I could tell with the stock exhaust manifold and single pipe. I wasn't after power tho, so didn't care. I was after mpg, and to that end it did good.
     
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  9. old yellow 78

    old yellow 78 Well-Known Member

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    Wow! Thanks everyone for the replies! ;) As I said, I am not a mechanic, but I can do some things. Replacing things such as shocks, water pumps, starters, etc., is no problem, but I have never rebuilt any parts of an engine, or swapped one out. Probably the most involved engine work that I have ever done was replace a burnt valve in a Chevy 283 several centuries ago.

    Likely this type of engine swap would be no problem for many of you, but it's not something that I would have the ability to take on myself (either skill or time-wise). That being said, it sounds like it could be done without too much hassle... maybe.

    But, after reading some of the comments above, I am thinking that it might not be such a good idea. The Super Six only has about 30K miles on it, and I like that it is original to OY. Also, it sounds like I could accomplish some more power by changing some gearing and exhaust. Both likely much less expensive and less work that pulling the engine and replacing it.

    As far as I know, OY still has it's original station wagon rear diff, which I thought was actually desirable being that it is a wagon with the higher (?) gearing. I don't quite understand all of the info that AJ/FormS kindly took the time to post, but I appreciate it. What I do get from it is that I am assuming that by changing out the A833 gearing and possibly the gears in the rear, this would make a noticeable difference. OY already has lots of torque in first, and second, but poops out in third, and then in forth... well, there is a reason it is called an "overdrive". First gear peaks the RPM's very quickly and actually seems to me to be too low. Second gear pulls really nicely. Third is where my disappointment comes in. It just seems to lose it's power. Forth is really only for cruising on the flats, and hills require downshifting to third.

    The exhaust is stock of course. It used to have a stock "resonator" at the far rear end in addition to the muffler and cat, but I took it off. I didn't notice any difference. The exhaust is supposed to be a bigger diameter because it is a Super Six, but not sure that really makes any difference either. I am wondering if a header would make any difference? Would the manifold have to be split and duels installed, or would a single header be adequate?

    I'm also aware that in another post I was just complaining about not having enough spare time to even put my door panels on much less replace the engine, but I've been wondering about this type of swap for a long time, so I appreciate everyone's input. I am slowly getting around to making OY exactly what I want. :) Getting good info and advice here keeps me from going too far off into the weeds. ;)

    IMG_20190914_173621174.jpg
     
    Last edited: Oct 30, 2019
  10. AJ/FormS

    AJ/FormS Well-Known Member

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    Pooping out in third is typical of that overdrive box because it's actually direct or straight thru. So if the gears are hiway-type even the 318s have trouble with it. And the 3.09 low gear does exactly what you describe.
    This is the problem; from 3.09 to .73 is a range of 4.23 and that is just about too much for just 4 gears.
    Consider Mopars;
    close-ration box, has a range from 2.47 to 1.00 or just 2.47, and is great for 4 gears.
    the regular 2.66/direct 4th is 2.66 and you guessed it
    the 3.09/direct is 3.09
    Using the od box invariably leads to having to bias it either for the bottom-end or the top-end; and the slanty doesn't really have any top-end so it just dies.
    Your engine would really like the Commando box.

    Look at this way; With the current box, and upshifting at 3600, and assuming 3.23 gears;
    First will get you to 29mph. When you shift the Rs will fall to 1944 and then it will pull to 54 mph. At the 2-3 shift, the Rs will fall to 2156, and now the engine pulls to say 65mph@2600, and overdrive is 1900. So you can see that after every shift the slanty is forced into a very low-performance rpm range, and has to pull a long way in each gear. Your powerband has to be from 1944 to 3600=1656 rpm

    Lets try it with the Commando box; and 3600 /3.23s again.
    First; again gets you 29 mph. At the 1-2 shift the Rs will now fall to 2240 (that's 300 rpm higher now). Second will pull to 47(instead of 54), and on the 2-3 shift the Rs will fall to 2625(instead of 2156). Third gear will now pull to 65@3650. And then you stuff it into Fourth and the Rs fall to 2610. Your powerband has to be from 2240 to 3600=1360; that is to say 296 rpm, or 18%, smaller.
    But look at the pulls in each gear;
    First gear is the same, from zero to 29mph.
    Second is from 29 to 47=18mph; instead of 29 to 54=26mph,
    and third is from 47 to 65=18mph, versus from 54 to 65=9mph.
    So you don't get that loooooooooong second gear pull/ short pull to 65.

    Lets try the commando with 3.73s
    First pulls to 26@3600. the Rs fall to 2237, and then she pulls to 42mph. The Rs fall to 2626 and then she pulls to 57mph. The Rs fall to 2570, and she pulls to 65=3010, or 57@2640
    Now check out the pulls; The powerband is from 2237 to 3600=1360rpm and first pulls 26mph, second is 16, and third is 15, and fourth is 8 to 65 or zero if you stuff it into 4th at 57mph.
    So now you can see that the engine is 300 rpm further up the rpm band with 3.73 versus 3.23s;
    And the pulls in each gear are reduced by 2 or 3mph.
    What this all amounts to is more average power put down during the run ...... so the ET should be lower

    Ok so now compare the current-box,third-gear road-gear of 1.00x3.23=3.23 to the Commando third-gear of 1.40x3.73=5.22.. This is 62% increase in third-gear torque-multiplication. Your slanty will feel 62% bigger, anytime it is in third gear.
    Waitaminit; the Commando/3.73 will feel in 5.22 third gear; as it now does in 1.67x3.23=5.39 second gear; whoot-whoot.
    BadaBOOM!
    Here's how it looks;
    od Box/guessing 3.23s;----------9.98----5.39----3.23----2.36;65=1900
    Commando /3.23 ----- 9.98----6.20----4.52---3.23;----65=2610/55=2210
    Commando/3.55; ------10.97----6.82----4.97----3.55;---- 65=2870/ 55=2430
    Regular 2.66/3.55s ------ 9.44----6.82----4.97----3.55;---- 65=2870/ 55=2430
    Regular plus 3.73s; ------ 9.92----7.16----5.22----3.73;---- 65=3010/ 55=2550
    Commando/3.73; ------ 11.52----7.16----5.22----3.73;------ as above
    Eyeball the chart and see whatcha think
     
    Last edited: Oct 31, 2019
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  11. Oldiron440

    Oldiron440 Well-Known Member

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    AJ, I know what your trying to say but you're very hard to follow.
     
  12. BudW

    BudW Moderator Staff Member

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    There is a ton of different directions one could go with this.

    K-Frame
    There are only /6 and small block K-frames – with a few but minor changes along the years. I would use what you have and use Schumacher mounts (easiest and most cost-effective route).
    '73 & UP A,B,F,M, J-Body Products then scroll down a bit to S6 to 318 (or 340/360, which is slightly different), P/N A73A6 (318) or A73LA6 (360) – about $180.00 (US).

    The existing suspension can and will work – but in my opinion and IF you plan on driving the car a bit spirited at times, I do recommend getting FFI torsion bars and front/rear sway bars – but that could be $,$$$ (optional).

    Your existing brakes can and will work – but in my opinion and IF you plan on driving car a bit like I do, upgrading to 11¾” front rotors and 11” rear drum brakes are worth it (if not other routes/methods). Bigger brakes will require 15” wheels, though (optional).

    Your existing differential (8¼”) should work fine with a stock or mild 360. A better differential gear ratio sometimes makes a larger difference than engine size does (depending on what gear ratio you currently have) - see earlier posts.
    The gear ratio options for ’78 (for 8¼”) are: 2.45, 2.71, 2.94, 3.21 or 3.55:1. Sense you have a manual transmission – I would suspect you have either 2.94 or 3.21 gears (which is what most standards use).
    The 360 would prefer to have 3.21 or 3.55 gears (3.55’s (or 4.10's) would be fun).

    The existing A833-OD will work for a stock or a mild 360 build. The gear ratios are not the best for a performance small block nor is the A833-OD strong enough to hold up to a performance 360. Stock is fine, though. If you are making a performance 360 – you might be best to get a A833 (non-O/D) because of the strength and gear ratios being more to what engine will need.
    When I convert my wagon to manual, I'm looking at the Magnum (brand) 6-speed (what is used in todays Mustangs, Camaros, Challengers, etc.) so I can have the decent gear ratios, a good low gear and two (2) overdrives. Also the Tremec Magnum 6-speed can handle my big block without issues (this might be overkill for you, though).

    A small block bell housing (with O/D) and flywheel will be needed. The bell should be easy to find for a lot were used on the ‘80’s pickups. If using a stock 360 Magnum – it will take a special balanced flywheel (shouldn’t be too hard to find).

    The Z-Bar is the hard part. V-8 manual transmission F-bodies were not made in mass numbers. Finding a Z-bar will be hard - it might be easier to make one. I have seen a lot of handmade Z-bars, mainly for A, B and E-bodies – so it can be done. I’m planning on using/adapting hydraulics from a manual Dakota pickup when I convert my wagon to a manual. That hasn’t been tackled yet – so I might be in for a surprise (good or bad).

    Any 360 car (’71-81) oil pan will work. Pickup, van or motorhome pan will not work. Here is a new (repop) pan for $51 (US) and I’m sure there are others out there. Fits 1971-1980 Chrysler Mopar SB Small Block 360 Engine Oil Pan Raw | eBay

    The radiator necks are in different locations. A radiator shop could re-work your existing radiator – but I recommend getting a new one (either way will work). The big item here is if your car currently has a 26” wide radiator (preferred) or an 18”, 20” or 22” version. If your car came with factory A/C, it should already have the wider radiator. My 318 came with an 18” radiator – which will need some core support work done before I drop in the big block.

    The wiring will not be too hard to adapt (see post # 4).

    The throttle cable will be a different length. You might be able to use yours, but it might be too long.


    Now you have choices to make:
    All Magnum engines came fuel injected (with the beer keg intake). If converting to the Magnum fuel injection, it would be a sweet smooth driving and running car, but some electrical and fuel work will be needed to make it fit. It has been done and it works well – but car will also stand out in a car show.
    Intake Magnum.jpg
    The Magnum beer keg
    In Long Ram.jpg
    Which is directly related to the original Chrysler long ram intake (only coiled up).

    Most people will install an aftermarket 4-bbl intake and a carburetor (or a 4-bbl appearing fuel injection set) – which doing so will make car not stand out at a car show as much. Some people prefer the older 4-bbl look, some people don’t.
    360 Magnum 4bbl.jpg
    Magnum with a 4-bbl intake. Note: this one has the older timing cover setup (more below).
    318 Magnum FI van.jpg
    Magnum engine with original beer keg intake (which is hard to see in car).

    The next choice will be to use ‘70/80’s timing cover/accessories/pulley system or convert to the Magnum timing cover/accessories/pulley system (serpentine drive belt). The older system looks more in place for our cars, but the new system is more efficient (but harder to convert to because of hose modifications (A/C and P/S) and so forth).

    The good news is you don’t have to worry about kickdown linkage (a huge plus).


    A fresh but stock 360 Magnum (either fuel injected or carbureted) might give you more power than expecting. Also, you could make the 360 Magnum look just like your wagon came from factory with a small block (if wanted).
    If you wanted more power than stock, then the sky is the limit.

    The 318 Magnum vs. 360 Magnum is only 42 ci – so not a lot of difference in power. If you can find a 360 for same price as 318 – then go for the 360. Otherwise, I interchange the terms

    The 318 Magnum and 360 uses different engine mounts – so don’t purchase the mount kit until engine has been obtained. The 318 and 360 uses different oil pans. Lastly, the 360 is externally balanced – which the biggest issue for you would be the correct flywheel.
    BudW
     
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  13. AJ/FormS

    AJ/FormS Well-Known Member

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    Yeah I know what I'm trying to say also, but I also have a hard time following my blather.

    Basically;
    it's about putting down the most amount of average power between two places on your speedometer.
    With hiways gears and the OD box, between zero and 60 on the speed-O, the engine only goes thru the power peak 1.5 times
    With 4.10s and the "regular" box, It goes thru it 2.5 times.
    So even tho the 318 might make twice the power of the slanty,if you don't need the cruise rpm, or the V8 excess power,then gears can almost level the playing field.
    Any better?

    Now; if OY was mine; I have a 400hp 360/ Commando/Gvod/ 3.55s just sitting here waiting for a sweeeet roller. :)
     
    Last edited: Nov 2, 2019
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  14. Oldiron440

    Oldiron440 Well-Known Member

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    Much better, yep I've got a snotty 440 and standard 833s looking for something to do.
    It would make it a quick grocery getter.
     
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  15. old yellow 78

    old yellow 78 Well-Known Member

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    I really appreciate the vast amount of info you guys are posting in response to this thread! I am learning quite a lot here. and I'll ask you to bear with me while I keep learning.
    I think I understand what you are saying here in your post AJ/FormS. Basically, I think you are saying the stock A833OD "box" has gearing that is too widespread for the /6 to manage well. The RPM's in each successive gear shift up drop too low for the engine to maintain it's pull. What I am not clear on yet is the "3.23, 3.55, and 3.73" numbers. Are you referring to the differential gearing? Also AJ/FormS, are you saying that to simply replace the A833OD trans with a "Commando" trans would accomplish basically what I am looking for?
    As always BudW, you provide an encyclopedia's worth of information! To know that the existing K frame, suspension, and brakes would likely be adequate for what I want is great to know.
    Ok, so what you are saying here is that changing out the A833OD transmission might just do it for me? Basically you are confirming what I am understanding from AJ/FormS also? If so, that would be GREAT! I have already replaced a manual transmission in another car in the past, and that is much more doable for me than replacing the engine-plus. Of course, I already have another spare A833OD trans in my parts hoard which would then become even more useless, but who cares? How would I tell what gear ratio I have in my 8 1/4 differential now? How would I go about changing that if needed?
    My good friend with the blue '75 Dart Sport also has a '93 Dodge Ram pickup with a fuel injected Magnum 318 and Torqueflight in it.
    IMG_20180729_113202200.jpg
    It is the last year for the ancient old body style, but the engine itself only has about 70K miles on it and runs really well. We have talked about transplanting that Magnum into his Dart, or OY for a while. He obviously gets first dibs on it, but I have thought that it would be a LOT of fun to have that engine in OY!
     
    Last edited: Nov 1, 2019
  16. AJ/FormS

    AJ/FormS Well-Known Member

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    Rear gears are torque multipliers just like the transmission gears are; except you can't shift them on the fly. The bigger the number the rear gear, the more rapidly the same engine will power thru it.

    Lets say your engine makes 100ftlbs at take off, whatever low rpm that might be; I'll guess 1800. The overdrive transmission low gear will multiply that by 3.09, and the rear gear will multiply it again by whatever ratio it is, say3.23. So the equation looks like
    100x3.09x3.23=998 ftlbs into the axles.
    Say you changed that rear gear to 4.10s, then
    100x3.09x4.10=1267 ftlbs,. This is an increase of 26%
    Say you had a 318 and 2.76s,and slipped it out at 148ftlbs. Then
    148x3.09x2.76= 1267ftlbs at the rear axle
    Now, the difference here is that the slanty is near close to full power, while the 318 is closer to half-power.
    There is no substitute for cubic inches. and notice I changed the 318 to 2.76 gears to prove the point. If the 318 also had 3.23s then
    148x3.09x3.23=1477. this is ~17% over the slanty with 4.10s

    So you have two choices;either
    the slanty with gears, or
    the 318 and leave the gears
    but the 318 will always be loafing fir the same acceleration that takes full power on the slanty.
    It just depends on if you need the excess torque of the 318... or not.
    This is first gear only, at take off only. The previous post still applies.
     
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  17. Oldiron440

    Oldiron440 Well-Known Member

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    You can have the best of both worlds by installing a overdrive after the transmission and using a non overdrive transmission effectively giving you 8 gear choices.
     
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  18. barbee6043

    barbee6043 Well-Known Member

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    Making this swap is lots of parts and labor ( labor you said you have to pay for). If you are still considering this, you might check to see IF Schumaker has ever got back to making is engine swap brackets. Otherwise you are looking at a K member change and all that is involved there too.
     
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  19. XfbodyX

    XfbodyX Well-Known Member

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    Since your gonna pay for labor, id consider just finding a nice v8 twin to OY and have two.

    Its not a hard swap for anyone or any shop but I can see some shops looking it as a big money op. and really cost ya and yes the small simple junk gets billed as much as the hard stuff so I could see all the fiddle faddle costing alot.

    Just for kicks why not inquire at a shop and see what they say, I ,might guess some may say why? or its just not worth the cost.
     
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  20. BudW

    BudW Moderator Staff Member

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    The A833-OD is a fine transmission (for the time) but the difference between gear changes is, well, too much of a span. If Chrysler taken the non-O/D A833 and put additional gear in it (making it 4-speed plus additional O/D, or a 5-speed) – then PURFECT, which is pretty much what most 5-speed transmissions are. The Tremec Magnum 6-speed manual transmission is basically a 5-speed but with a second O/D gear in it (two overdrive ratios). Either the 5-speed or 6-speed allows you to lower the gear ratio (higher number) for better takeoffs (more chances to keep engine in the powerband) and have overdrive as well.
    The problem is none of the 5-speeds or 6-speeds are a direct bolt-in affair.

    I think the ‘ate ‘80’s/90’s Dakota/pickup 5-speeds might be a close bolt-in affair, and I might have the opportunity to find out shortly. I just don’t know for sure … yet.

    What I think AJ/FormS is saying (and myself) is before going through the trouble of engine replacement, is to replace the differential gear set first. I would bet (but no more than a quarter, sense I’m not a betting guy) your wagon has a 2.94:1 gear set in your 8¼” differential. Installing a 3.21 gear set will make a difference. 3.55’s is a fun gear set. 4:10’s will put a wide smile on your face on takeoff.

    If you change gear sets and is still not satisfied, then I would consider engine upgrade. Even then, your engine upgrade will want the better gear set anyway so that part has already been taken care of.


    The best way to determine your current gear ratio is to remove the differential inspection cover. Chrysler says you are to change the differential fluid every 30k miles to begin with and check differential fluid level every oil change. I would say you might be due for fluid service anyway.

    Once the cover is off, rotate the propeller shaft until you find some numbers stamped on the ring gear, like this:
    7.25  3.23.jpg
    The blue arrow will be part number. The red circle is the gear ratio. The white line is the date of manufacture (which should be a bit before vehicle build date).

    20160726_100304.jpg

    20160726_100237.jpg
    This 8¼” came from a ’80 F wagon. This is the numbers on it: “3723584-2.45 8 14 79” (the 79 is off the picture) which would be 3723584 is ring gear part number. 2.45 is gear ratio. Manufacture date was 8-14-79.
    This one is an open (non-limited slip) differential.
    Note: 2.45 ratio is a dog. You might as well be towing a pickup behind your vehicle, permanently. 2.2 gears are even worse.

    Note: I will not recommend going back with an open differential if you are performing an overhaul or gear change. There is so many advantages to having limited slip (if not already present) that I must recommend upgrading to it (again, if not present). A majority of FMJ's did not come with limited slip.
    My ’77 wagon was built with limited slip (yahoo!).


    FYI, that is a nice pickup. I’d have a frown if someone parted out the vehicle.
    BudW
     
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