55-64 gm rearend what is it????

Somebody gave me this rearend and told me it was a ford 9"well I found out it wasn't when I saw the big GM on the third member and I figured it out that it was a 55-64 GM rear I don't have a GM parts book to tell me what this is. OK the pn#on the third member is 30707306 Gm3, on the housing on the otherside is BA609 Any and all help would be appreciated

 

count the bolts....

 

It's got 10

 

If it has leaf spring perches, it's a 55-57.........57 has a drain plug on bottom.

If it has brackets for trailing arms, 58-64.

That's all I know............

 

ok then its a 10bolt GM rear...lift it up and spin one wheel and see if its a posi..i doubt it..the 10 bolt came in the economy cars with the 6cyl. and some of the 8cyl.....ex. i got a 65 biscayne...6cyl. with the 10bolt rear...non posi

 

thanks thats more than I knew It has the drain plug and somebody did some funky welding where the spring perches are It has some half inch plates welded on where the spring perches are anybody know what the rough value of this item?

 

most posi in that style had a p case....should be a tag on it with other info.... brandon

 

Not much..................they are not a real strong piece...........The pot type Chevy rear was popular with rodders, because the whole pot could be changed easily, and guys would have a few with different ratios. The Olds, Buick, Pontiac rears of the same years were much stronger.

 

not much dosn't tell me nuthin

 

Looks something like this?




I ended up with one in this truck when i bought it. here is what I found out about it.

http://www.jalopyjournal.com/forum/showthread.php?t=201274

 

OK probably nothing I have two I can't give away, mine are out of 60 chevy's....they are not very strong.

 

They're worth their weight in short iron. Thrown in a car, 9 cents a pound, the last price I was quoted for scrap.

 

I think that 3707306 third member casting number may have been 1956-only. If the third member is original to the housing, you got a 1956 Chevy rear. If it's never been apart, it is Non-posi, because posi wasn't available in '56.

 

All of these rearends have the save number of bolts. When refering to a 10 bolt or 12 bolt your are refering to the units built later, not these. These, 55-64 style rears are not real strong. Many have a 3.36 ratio but others are avalible. You gunna race it? Buy better. Just drive it. Should last, and the price was right. Have this type in my 58 Impala for 50 years now. Works well. I don't hole shot it with slicks. Know my limitation here. Hell, the 348 wouldn't anyway.

10 bolt info isn't correct here, sorry. My 67 Olds 442 new came with a 10 bolt, 3.91 Posi. Olds rears of this vintage are 10 bolts. Can't speak for Buick and Pontiac. Chevy had both 10 and 12 bolt rears. **10 bolt "O type" and Chevys, aren't the same either.**
Lotsa info on this stuff.

 

Here is a GMT55 truck rear end thats in my 60 pick up

 

This is what I got

 

3707306 is a 55-64 CAR rearend with a drop out center, and no rear cover.
There should be a date code cast into it, something like H242 for example. Thats the date code for it. 55-56 versions have different axle bearings and back plates that the 57-64 ones, and only the 55-57 ones had leaf springs.

They are fine for most applications under 300 lb/ft of torque, more if it doesn't hook up...

 

this is what I got

 

I have the same rearend in my project. It's definitely a '56 as already mentioned. The B indicates it was built in New York (an A instead would indicate it was built in Detroit. The second letter indicates the gear ratio (A=3.70, B=3.55, C=4.11). The 609 is the date code (6=June, 09=ninth day). I have the 3.70 version too.

 

Good for a driver. The axle bearing on these are very high..1955-6 had one bearing and 57 another.

 

Thanks everybody for your input on this rearend but this piece won't fit with my project so I'm going to try and get rid of it. Thanks fordclevor

 

try and find someone to sell it to. they work great in roadsters.
even though not the most desirable rearend you should be able to get 50-75 dollars. would be a shame to see it scrapped.
rusty parts need salvation just like rusty cars.

 

if nothing else the center section has some value due to the weakeness,,, they break, and people just want to pop in another on the cheap rather than rebuid it.

posi's have a P on the case. worth 3-400 depending on who you talk to.

toss the housing. try to sell the axles and center... that's what I'd do

 

Actually if it's a 5-6-7 car rearend it's an easy swap to any 42-54 Chevy to go to open drive, it might be worth selling for that use. May fit earlier, too.