jaycenk

Hello,
I have what I believe to be a 1980 or 81 model year bat-wing rear diff.
I have questions and would like some fact checks if I am wrong on any info.
From what I understand it's a DANA 44 Non HD.
It has the numbers as follows on the ring gear
8 21 80 DANA D 37792A A3R336 43 15
Saw info on another forum that says:
8 21 80: is the build date
DANA: self explanatory
D: DANA Logo?
37792A: Unknown
A3R336 Unknown
43: Ring Tooth count
15: Pinion tooth count

From what I read this is a 2.87 ratio rear. Good for A3's not for the Head and cammed LT1 and 4l60E engine trans package I have for my build.

Car is a C3 and is a full project car. Nothing Original or matching ground up rebuild.
Tub, bird cage and VIN on cage are 1969 Convertible. The frame is 1980 to 1982.

I am planning on making it an automatic car with a 4l60E. Engine and trans are from a 97 Camaro I have played around with for years. Camaro has 3.23 gears and 2200 stall. This head and cam package seems like it would love a ratio between 3.50 to 3.73 gears with 3000 to 3500 stall converter.

I would like to know who can rebuild this rear I have Near Tampa FL OR if there is a company outside of Tampa FL that rebuilds them reliably.
I want the guy who is 1 and done with no worries on this rebuild. NO BS. I have put up with enough of that B.S while loosing thousands to tool bag engine builders and trans builders on my Camaro.
I see a lot of parts supply companies advertising that they rebuild these rear but I doubt it's actually them rebuilding it. Companies like ZIP corvette, ect.. DO they do their own work or who is doing the work for them?
Are they any good? and are there other options worth looking into?

Any help would be appreciated.
Thanks in Advance

69427

Drop a PM to Tracdogg2 (Mike in Texas). He's got a good reputation, and can probably help you out.

Street Rat

Mike can build the Dana 44 to take some power reliably.

You can also get a kit to put the earlier model rear ends (stronger) into the '80-'82 C3s.

MotorHead

I wouldn't be so fast as to changing the dif until you know what gear is in it. If 1980 or so frame and rear it could be a 3.08 and multiplied buy the 3.23 of the tranny you have the perfect street strip comb of ~10:1.

Kept in good condition an aluminum Dana 44 is much stronger than than most give it credit. I have taken mine with 600HP to the dragstrip with a 3.08 rear gear. Now I granny launched it and the dif still saw more than 500 ft/lbs of torque when it hooked up.

If you are drag racing a lot then a steeper rear gear might be in order

BlackC3vette

My 80 has a 4 speed with an original 3.07 rear. It is an aluminum rear built for an engine with 190hp. Call Mike or send him a PM (tracdogg2), he is a wealth of information. But, he is not a big fan of the 80 aluminum rear with health hp. Regardless, give him a call an he can help formulate a plan.

jaycenk

Good to know. I will be sending him a message.
Thanks!

jaycenk

Who might sell this Kit? Is there a site Or is it a machine by request part?
Thanks for the info!

jaycenk

sorry if I miss spoke, The 3.23 is the rear gear ratio in the Camaro I am taking the power train out of.
I think the 4l60E OD gear at lockup is .70
I have a lot of miles with that gear in that car and second gear runs out to 80 at 6300 RPMs with this 4l60E and lock up in OD is at 55mph at about 1600rpms (4th gen Camaro Tachs are always off by couple hundred). 55 is a little high for lockup setting to be programmed at but it is only a stock bottom end LT1 with big valve heads and a healthy Cam.
I used to have a 383 bottom end in the engine and the trans was programmed to lock up at 48 and that is well under under 1600 RPMs but the torque that engine made was unreal. It was like my turbo Diesel. You could just add a little throttle with out having to unlock the converter and she pulled.

This car wont see much if any track use. Its going to be a fun driver with an automatic lol. Thinking at least 3.50 ratio range just so it's good and sporty but will go down the highway nice.

Street Rat

Duntov Motor Company has the kit.

http://www.duntovmotors.com/differentials-80-82.php

The Money Pit

I have been running my aluminum Dana for twenty years and have not had any issue with strength. The 406 I now run is in the 540 horsepower range, and I have a 3000 stall and th400.....and MT 295 55 15 drag radials. I have never "raced" the car, but do on occasion blow the cobwebs out......

The point is if driven with a reasonable respect for the power on tap,...the aluminum rear will take a ton of power. If I were you, I'd do a set of 3.70's with the OD trans. I'm running that now and I have no OD, but my cam is pretty big. I did have a 700r4 for a while,....but it did not get along well with the 406..........

Kid Vette

Interesting, they don't mention the difference in driveshaft length.



Or that the front bracket mounting hole won't line up.

BlackC3vette

The photo with the two diffs side by side shows the 1980 on the right. The 80 has the front mount as part of the casting, it is not a separate piece like the one on the left. I would call to confirm what exactly you would be getting before placing any order.

jaycenk

LOL Yeah 700r4 and 4l60/4l60e are more or less the same trans so I know what you mean. Blew 3 4l60e's up already mainly because of poor build quality but also 500 ft lbs out of the 383 didn't help either.
Much less torque on this set up now but I'm getting that itch to build another 383 So it needs to take the power.
Good to know the 44 can hold the power if done right.

jaycenk

Good info because I think my father has an Eaton unit sitting around not in use.

jaycenk

Oh yeah. Been bit by that bug one too many times!!!

Gale Banks 80'

So You have a 2:86 Ratio so that means its an 81 or 82 as all 80's were 3:07. The weakest part is the 1/2 shaft U-Joints and GM put larger ones in the 4 speed cars and all 1982's. They use the 1350 size. An easy way to tell is to remove one of the U-joint Straps and check the Bolt. If it 1/4" its a 1330 and if its 5/16" then its the more desired 1350. The vast majority of these cars were 1330's. This could be a deal breaker on what to do. The 79 and older were all 1350, so a conversion using your batwing will also take care of this at the same time.

jaycenk

I'm almost positive its the smaller size. One of the bolts broke off in the sub shaft when I was removing the straps and I thought to my self how in the hell did that little POS break lol.
The rear is out of the car and the trailing arms are off the car. I'll have to price it all out and see what parts I have available from my father. he has a ton of stuff in crates from the 10 plus vettes he has built for race and street in the past 20 years.
I find out this weekend.
Thanks for the info.