Swap a 4 spd. for my 3 spd.

HotRodChomper

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Hey there,

I am new to the site and also a new owner of a 1977 Dodge Aspen R/T. 318/3spd. car. I did a little research on the 3 spds. and I know that they were the standard transmissions in many of the earlier Mopar muscle cars. It seems like there was a stouter version also, I believe it was either a 230 or 203, not certain about any of that. I am wondering if 4spd swap would be a worth while (performance, drivability etc.) swap. If so what 833 will swap across the board??

Thank you in advance...

20210717_155651.jpg


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BudW

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The '77 passenger cars had two different manual transmission options, The A230 3-speed and A833(OD) 4-speed with overdrive.
Both came in two different lengths: F-body – which is same length as A-body (short, or A904 length) and B-body (long, or A727 length).

1977 gear ratios:
A230
First – 3.08
Second – 1.70
Third – 1.00
Reverse – 2.90

A833(OD)
First – 3.09
Second – 1.67
Third – 1.00
Forth – 0.71
Reverse – 3.00

I do not see much of any difference between the ratios to make much of an performance difference, except for highway speeds (OD). Now an older A833 4-speed will have different ratios which might make a answer to your question

The '77 3-speeds had an option of either column shift or floor shift (like yours is). With the exception of the diameter of the front bearing retainer (vs bell housing bearing retainer hole) which might be different, a short tail-housing A833 (OD or not) should fit right in. You will need to find a 4-speed shifter, though.

A long tail-housing A833 (OD or not) will also fit in place, but shifter mounting will be in a different location (and propeller shaft will be shorter).
BudW
 

HotRodChomper

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Right on!

Thank you for the information...I would like to make it into a driver, so the OD gear may be the answer in a 4spd.

Cheers-Ted
 

Aspen500

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An advantage to having a 4 speed O/D is, you could change the rear gears to a lower (higher numerical) ratio which will give better acceleration but keep highway rpm lower. If you have (for example) 2.92 now and went to 3.23, the off the line feel will be much better.
 

HotRodChomper

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Thanks, had an idea that's what it would do. Don't know what type of gearing is in this car, haven't checked it out. I don't know what the typical gear set for these standard transmission cars were...

Thnx you...
 

Aspen500

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My Aspen was originally a 225/4-speed O/D and it had 3.23 (in the puny 7 1/4" axle). Normally 3-speed manual trans cars have a 2.XX ratio (I'm referencing A-bodies though) but the only way to find out for sure is to check it.
 

BudW

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In '77, a 318 2-bbl 3-speed manual came standard with 2.9. A 3.2 or 3.2 with limited slip was only two options.

I have nothing to say otherwise, but I suspect the 2.9 is an 7-1/4", where as I also suspect either 3.2 options might be 8-1/4" (but again, nothing for or against this last sentence).

There is a small chance there might be a tag under one of the inspection cover bolts with gear ratio on it, but I wouldn't hold my breath for that. About the only way to know what the gear ratio is, is to remove the inspection cover. On the ring gear, it will be stamped what the ratio is.
7.25 3.23.jpg

Blue is part number (not that important), red is ratio and white is date gear was made.

In '77, the 7-1/4" has 9-bolts attaching the inspection cover and 2-1/2" diameter axle tubes.
76-81 7.25 RDS12775.jpg

The 8-1/4" will have an oval shaped shaped inspection cover with 10-bolts and 3" diameter axle tubes.
63-12 8.25 RDS55047.jpg

BudW
 

Aspen500

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At least in '79, the 3.23 was either standard or, it may have been optional. No idea which but it also could have depended on the engine. My old 7 1/4" was 3.23 and the stump puller (not) CA emission 90 hp 225 my Aspen had needed every ounce of that ratio, LOL.
 

HotRodChomper

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Great info.
Man I am impressed by the vast amount of knowledge that the members have on this site.

The guy I bought the car from referred to the rear differential as having the bigger and better, "corporate " rearend. Not knowing much about these F bodies, I assumed and was hoping it had a 8 3/4. My research showed looks like they may have only installed 8 3/4 differential up to 1974.

What's the deal with the 8 1/4, assuming that is what is under the car. Is it stout enough for a mid 300 hp engine?

BTW, The car is actually sitting on my property and I only get to look at it on the weekends, when I go to work on the property. I have yet to do a full cleaning and maintenance on the Aspen...

HRC
 

BudW

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The 7-1/4" differential is not a very strong unit. I have seen /6's break 'em.
The 8-1/4" diff is a pretty good unit and is still used today on many pickups and Jeeps.
These are the only two factory differentials used in FMJ's. If you currently have a 7-1/4", I would recommend looking for an 8-1/4" (or bigger) and stick under the garage work bench to have on hand when the 7-1/4" blows up.

The 8-3/4" is a very strong diff, and was phased out in '72 except for E-bodies.
The 9-3/4" (Dana 60) is almost bullet proof and ended car production in '72 (but is still used in pickups today).
Neither the 8-3/4" or Dana 60's came in FMJ's - but one from a '66-70 B-body will fit into our cars with very little modifications.

Some people have had good luck with using the Ford 8.8" diff - but I don't have any experience with them.
BudW
 

HotRodChomper

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Once again thanks for the info. I had a decent working knowledge of the 8 3/4 and Dana availability but had no knowledge of the 8 1/4.

Have you ever heard of the 8 1/4 being called a "corporate" differential?

If my car has the 8 1/4, I will try and make that work. Hopefully it has the lower gearing too

Cheers...Ted
 

BudW

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The 7-1/4", 8-1/4", 8-3/4" and 9-1/4" are all "corporate" axles, meaning they all were built in-house. The Dana's were not (ie: were made by Spicer/Dana).

The 9-1/4" is considered to be a "poor man's Dana" - but were used mostly by pickups (still today), Vans, some B and some C-bodies. It is too much work to get one to fit into an FMJ so I didn't mention it.

A lot of different Dana versions were used by Jeeps, so the Jeep crowd likes to toss the term "corporate" and Dana around a lot. The more common Jeep Dana's are D35 (7-1/2"), D44 (8-1/2") and D60.
BudW
 

Aspen500

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Had my 7 1/4 break back in the late '80's when the Aspen was still a S6/ 4 speed O/D. As mentioned, it had the 90hp version and I never abused it (how could you with that engine?). Was driving home, came around a corner and BANG, all done and there I sat. Driveshaft turned, car didn't move. Spider gears basically grenaded and it wasn't a pretty site when I took the cover off, lol.
 

Duke5A

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Grab a Ford 8.8 with disc brakes and have it reworked. You don't need a D60 for 350hp. Availability on these old Mopar axles is making them real hard to find.
 

Aspen500

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The Ford 8.8 is a very good axle, and strong. Worst problem I've ever really seen with them are the pinion and carrier bearings, (and sometimes axle shaft bearings) and those were usually on trucks that also backed boat trailers into the water. Water/oil mix is not a very good lubricant, lol.
 

AJ/FormS

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If you are gonna put a cam in the low-compression 318, you are gonna find out really quickly that the wide ratios of the Standard A230, and A833od, are indeed very wide .
In the 70s there was a second A230 available with closer ratios of 2.55-1.49-1.00
and the A833 was available with 3 other ratios;
3.09-1.92-1.40-1.00 Commando
2.66-1.91-1.39-1.00 the Standard box
2.47-1.77-1.34-1.00 AAR ( getting harder to find every year)
For the 318, I highly recommend the Commando. This will allow you to launch with 16% more authority than the Standard 2.66 low.

But be warned; when you start camming one of these low-compression 318s, they lose bottom-end very quickly, requiring more and more rear gear to get moving. The combination of a sagging bottom end, and the wide ratio trans is a sure recipe for disappointment.
The only cure for this is more compression.

Congradulations on what looks like a nice find.
 
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