1. mike2

    mike2 Well-Known Member

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    Does the front end of F body need any mods to convert to v8 small block from slant 6?
    I know mounts are changed, using shumacher mount kit, have v8 radiator , staying automatic. Thanks for any input
     
  2. M_Body_Coupe

    M_Body_Coupe Well-Known Member

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    On my M-body I needed to fabricate mounting plates for the rad. This is because the V8 had a wider openning in the front section whereas the /6 was narrower. This meant I was not able to simply bolt-up a V8 rad. No problem, easy task, here is how this turned out:

    1) plates
    rad_brackets.jpg

    2) rad mounted
    rad_mounted.jpg
     
  3. mike2

    mike2 Well-Known Member

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    Thanks. Will have to measure mine.
     
  4. DCAspen

    DCAspen Well-Known Member

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    22" Radiator will bolt right in,You probably have a 19" with the /6
     
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  5. M_Body_Coupe

    M_Body_Coupe Well-Known Member

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  6. mike2

    mike2 Well-Known Member

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    I have the spectra cu500. I will have to take out of box and double check. Was supposed to be for v8 volare with ac. Any suspension mods needed. Or just torsion bar adjustments ?
     
  7. Oldiron440

    Oldiron440 Well-Known Member

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    If your asking about front suspension it is the same for both I believe. I opened up the coresuport on my 76 F body for the hd rad for a 360 and it bolted in. It's possible that the ride hight will need a small adjustment.
    Edit: the holes for the hardware were in the coresuport, it was just the opening I had to modify.
     
    Last edited: Apr 10, 2018
  8. BudW

    BudW Moderator Staff Member

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    To convert a /6 FMJ to a small block:
    You will need either a V8 K-frame or the Schumacher mount kit (either one works well).

    Throttle cable (There may be other manufacturers, but Pioneer still makes new cables: CA-8414 for 2-bbl or CA-8422 for 4-bbl).

    Transmission kickdown linkage (3-piece or an aftermarket cable system). 2-bbl setups are easy to find. 4-bbl 3-piece setups, not so easy (or cheap) to find. If you are going 4-bbl, I recommend getting an aftermarket cable setup (unless you have already a source for parts).
    A V8 1-piece kickdown linkage system will not work in most FMJ cars.

    Wiring harness (or harness modifications – mainly for distributor pickup and engine oil pressure sender(s)).

    If the /6 had factory A/C and/or a towing package, it should already have the wide radiator/core support brackets welded in.
    Cars without A/C and without a towing package (like my ’77 318 wagon) – come with the narrow radiator/core support brackets welded in.
    If your car has the narrow radiator and you wish to go with the wider radiator (like I do), you will need to either make brackets (like what M_Body_Coupe made – BTW, nice work!), modify the existing core support brackets (Note: look, measure, look, measure and re-look and re-measure before any cutting) OR replace the two pieces/brackets with A/C parts (takes a bit of welding to perform this task).
    My plan is to perform the later, that is when I also get ready to modify the firewall (for A/C) and modify the transmission tunnel) for 5 or 6-speed manual conversion).
    Most /6 radiators has necks in different locations than V8’s have – so a different radiator might be needed.
    Note: there are a lot of V8 FMJ cars out there with a narrow radiator, so if you are not planning on using A/C, a narrow radiator might be fine.

    The transmission cooler lines will be different. There are companies who make repop cooler lines – or you can get that from another parts car.

    Pretty much all pulleys and brackets from a donor V8 car.

    The torsion bars and sway bars are the same – but you might need to crank up the torsion bars for the additional weight of the V8. Brakes will also be the same.
    Perform a search in forums for ride height adjustment or look in a FSM (Factory Service Manual).
    Note: I would perform a ride height measurement BEFORE any work is performed, so you can know where to adjust car back too, AFTER repairs have been performed.
    BudW


    P.S. take plenty of pictures (like 200?) from your donor car before and during part removal.
    Also, bag and tag your bolts, etc. It is more work but trust me, it will pay for itself in the end.
    Also, post pictures of your progress and/or post questions you have during your project.
     
  9. 4speedjim

    4speedjim Well-Known Member

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    You'll want an SB 904. The bell and starter mount different and are not interchangeable. Any Mopar starter is fine. Use your old one or get a "mini" off and v6 v8 88 up. Fortunately the 904s are very durable, affordable and everywhere. Driveshaft might need altered. The slip yoke interchanges with all 904s so keep that. Distributor wires ought to be fine. 7 1/4 or 8 1/4 rear axles both come behind 318 so that's ok either way.
     
  10. M_Body_Coupe

    M_Body_Coupe Well-Known Member

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    If you are staying with the 904 series of the transmission you will get the 2.75 1st gear ratio since beginning in 1980 all were offered with a low gear set (2.74 First and 1.54 Second) as standard equipment. The A998 and A999 units have more friction plates (4 and 5 respectively), so if you are looking for a little more holding power that is an option.
     
  11. 4speedjim

    4speedjim Well-Known Member

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    Lock up Torque Converter also came around about 1980 or 81 also, didn't it? Your doing a stock set up right? That lower 1st is good with the low RPM torque band of the 318.
    Edit; RPM
     
  12. mike2

    mike2 Well-Known Member

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    Thanks for the info, will have to get a longer throttle cable and some trans lines, was thinking could modify some Dart lines , they sell ew ones for 76 dart .
    Have a 72 904 rebuilding now , with a 2500 stall setup ,the 318 is a fresh 30 over magnum, with edelbrock magnum intake and a comp cam, cam is 210/220 duration 512 lift . Torque should be good.
     
  13. BudW

    BudW Moderator Staff Member

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    Drat, I forgot about the transmission differences. Good catch.

    Any 904/998/999 transmission (small block or /6) will have the same length propeller shaft length.
    Any FMJ manual transmission (3 or 4-speed) will also share the shorter 904 propeller shaft length.
    All 727’s will have a shorter propeller shaft.
    There is also a difference in propeller shaft lengths between 2 and 4-door cars as well between 7¼” and 8¼” differentials – or a possible total of 6 different propeller shaft lengths (that said, I hadn’t seen any 727’s with a 7¼” differential . . . yet). Maybe that is 9 different combinations – I give up, it’s been a long day.

    Lockup transmissions came out mid-year 1978. There was about ½ year of big block automatics made with lockup.
    It was optional for non-lockups for a few years after that (via special order).

    It has been my experience that most (ie: 95% or so), if the 904/998/999 transmission style has lockup, then it already has the low gear set (the sought after gear set) already installed. With that said, there is a small chance it doesn’t, especially in the late ‘70’s.



    On cooler lines - pretty much any A, B, E or FMJ-body line set will work.
    Some people are just picky about making sure it is exact to your year application.

    Personally – I don’t care how it looks (year wise) just as long as it works. Almost every other year, they ran the lines differently. I don’t think it makes a hill of beans difference what year or body type you use.

    All F-body’s and most M-bodies have transmission cooler lines that screw into the radiator. Somewhere in the ‘80’s, they changed and went to a short piece of rubber hose between the front part of cooler lines and radiator – which I recommend because it takes less stress from the metal cooler lines (less likely to have a metal line crack, somewhere) – but most cases, full metal cooler lines work fine.

    There is a small difference between 727 vs 904/998/999 cooler lines but in most cases you can make a small metal line adjustment to work in either case. If you have a choice, get the 727 version – for a bit more line bending flexibility (ie: a tad more line to bend, if needed).

    I do recommend keeping the amount of rubber hose and hose clamps as little or few as possible, especially for those with lockup transmissions. Each piece of hose and each hose clamp is another possible fluid leak. The fewer places for leakage, the better.
    BudW
     
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  14. 4speedjim

    4speedjim Well-Known Member

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    Oh nice! That combo will pull strong.
     
  15. 65 cuda

    65 cuda Member

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    i am going from a /6 to a v8 swap LA 360 motor from a 76 chrysler cordoba into my 65 barracuda and i was told to make sure wiring will need to be looked at especially dash wiring cuz where it connects to amp gauge terminals could possibly cause a fire
     
  16. 4speedjim

    4speedjim Well-Known Member

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    Modern cars, newer than the Cuda after IDK? '70- '72 they went to volt meter instead of an ammeter. IDK what you'd need to do differently, but that change to volt meter is the difference.