Are 4spd cars 100#'s lighter

[JohnnyDees]

I read in the older posts a couple of mentions of 4spd cars being 100#'s lighter than auto's? Is this true? and does anyone know the difference in weight between 833 o\d aluminum and iron 833 trans?

[skankweirdall]

I think if you use a cast iron 4 speed and a steel safety bell housing, steel sfi flywheel and clutch the weight is approximately the same as a 727 and converter. The 904 is about 50 lbs lighter. I don't see how the 4 speed car could be 100 lbs lighter. The aluminum housing shaves about 25 lbs off the 4 speeds weight, I believe. It's been quite awhile since I weighed all this stuff. My numbers may not be exact but the outcome is relatively the same regardless.

[6 packin]

As far as factory cars go there weigh more. I know that the E-body 4 speeds with big mills will have things like torque boxes and Dana's. Were the auto cars will have 8 3/4.

[kudah440]

i tell ya i was just out in the garage a little while ago, and i had to move around 2 4 speeds and a 727...oh my back hurts now, so i can tell you that dam 4 speed is way heavier...
but wow thats an awefully strange idea that the 4 spd would be lighter...

[JohnnyDees]

Thanks for the replies...I tried some lifting myself......The 4spd was heavy but the aluminum case o\d did seem pretty light in comparison.

[jelsr]

I'm with kudah440 on this one, the A-833 is a heavy rascal, and when he was moving them around in the garage he wasn't handling the bellhousing, flywheel, pressure plate, and disc. (another 70-80 lbs)

[340duster1]

I weighed an a-body aluminum O/D trans (aluminum case, cast iron tailshaft) it was 91 lbs. I don't remeber the exact weight of the cast iron a833, but I think it is 120lbs.

[Clair]

I think you're in the right ball park, at least for the A-body parts. I mailed a 68 A-body 4-spd to a buddy in Oregon and the thing weighed 149.5# with the shipping crate. I'd say the crate was in the 20-25# range, so that's damn close. As it works out, I just happen to have an aluminum case and an iron case (ball-n-trunion) out in the garage. I'll weigh them when I get home and post the results. That iron thing is a PIG.

Clair

[deadhorse66]

Yep. If you are looking to shave weight to get quicker, you are stuck. The auto weighs about the same as the iron sucker by the time you get everything else you need. And wouldn't you know that the aluminum cased 833 is geared really poorly, so that will kill the performance gains you would get from losing the weight from the iron case. It just depends on what you want to do with the car.

[JohnnyDees]

I've always had 4spd cars. But I gotta good deal on a 66 dart gt and couldn't pass it up. It is an auto car. I was going to convert to manual and use the o\d so I could run low gears and still get decent mileage. But it seems from what I'm hearing the 999 is a better choice. Just love bangin gears though. One last question before I put this to rest and sell my 4spd parts. In one of my last posts I said I was going to use the o\d for mileage and one of the replies said with my 3.23 sure grip the 904 and o\d trans should get about the same mileage could this be true?

Thanks for all the help gotta go write an ad for my 4spd conversion parts..............

[skankweirdall]

Originally posted by JohnnyDees
In one of my last posts I said I was going to use the o\d for mileage and one of the replies said with my 3.23 sure grip the 904 and o\d trans should get about the same mileage could this be true?

I think the O/D would get slightly better, but not much, especially considering the hassle of the conversion and the fact that O/D is really more like a 3 speed with really wide gear spacing.

[Tarrbabe]

Yes the 833 is a pig! But I love bacon, sausage, ham, etc. etc.!!! It is one of the strongest street transmissions ever made. I can't beleive that a 4 speed set-up could be lighter than an auto. I did read in some old mags. that the alum. case must be upgraded to take the torque of a hi-po engine but with the correct mods. it can take it. It can also be re-geared to the standard ratios.

Just thinking outloud.

[Clair]

OK. just got back from the garage, and here's what I found...
aluminum case = 14.0 #
aluminum tail = 6 #
iron case = 37 #
iron tail = 19 #
That makes the iron case trans 36 # heavier than the aluminum case trans. Using 340duster1's number of 91# for an aluminum trans with an iron tail, we get a total weight for an all-aluminum trans of 78 #, and an all-iron trans weight of 114 #. These are all for A-body applications. B's, C's, and E's will all have heavier tail shafts and trans output shafts, which would add maybe 15 # total, my guess.
Will a 999 make the same mileage as an OD? Only if the final drive with the 999 is 73% of the final drive behind the OD trans, and that's assuming 100% lockup on the 999, which ain't gonna happen. If you don't mind really WIDE ratios and BIG rpm drops between gears, the OD 4-spd is a good way to go. You can get them in iron or aluminum cases, I have both. Pay attention to the output shaft size, though. Some came with the 904-size slip yoke.
The way I'm going to generate a little better mileage for my daily driver (soon to be) 340 Valiant is with a 3.09:1 gearset from an early trans swapped in to an aluminum case and 2.94:1 rear gears. About 10% better than the 3.23's I've got in the car now, and the 3.09 first gear makes the 2.94's act like 3.7X's out of the hole if I were to keep using my close-ratio box that's in the car now I'm sure the weight reduction will be helpful on the autoX course, too.

Clair

[JohnnyDees]

I do have an o/d all aluminum 833 with 3.09 1st. I just weighed the whole thing on my bathroom scale and got 80#'s.

[Clair]

Thanks for the backup on the weight there, looks like we've got it tied down pretty tight. I was going to weigh my iron one (currently my only assembled trans), but it's weight and mine more than maxed out my wife's pretty chromey bathroom scale, and I didn't want to risk putting the trans on it directly... ;-)
All the OD's had the 3.09:1 first, then I think second was like 1.67:1... almost a 50% drop in RPM! 3rd is obviously 1:1, with a 33% drop and is more like a "regular" 4-speed box. The "regular" 3.09:1 boxes have a second gear of something like 1.92:1, a 38% drop. With the 2.94's out back, I'll only have to shift once on most autoX courses unless I exceed 65 MPH or so.

Clair

[340duster1]

I have an O/d 4spd in my 74 duster now. The gear spacing is quite wide (just like drivin a 3spd). Right now I have 2:somethings in the 71/4" rear which I will swap to a 3:92 8.25" in the next month or so. This should make it much more enjoyable to drive.

I like the idea of using the non o/d 3.09 gearset with 2:94 or 3:23's. If my o/d set-up and the 3:92's don't work out I will have to try that.

[JohnnyDees]

Earlier I said 80#'s it should be 88#'s for the aluminum 833 o\d. Also it will be for sale soon.