VCCA Home Forums TECHNICAL - 1945 AND NEWER 1961-1964 Could I get help I D-ing a rear end I just came across...

The guy I got it from specializes in 61 - 64 Impalas and he said it was 61-64. Casting #'s has the big GM with a T over a 7. To the left of that top # guessing date code I read it c or g 176 or 8 followed by 4 so my guess is C1764. Under that is 3725888. On the opposite side is a flat surface with stamped #'s BB0319. thanks in advance.

I found on another site I believe it was the tri 5 that the stamped #'s BB refer to 3.36 ratio built in Buffalo but not sure of the following 0319 #'s maybe date code 03 March, 19? Sort of goes along with the cast date code
of C March, 17 which I have read they cast on certain dates then actually stamped build dates. Makes sense but it seems that there should be only one # following the 17 which would be the last number of the year cast.
But I have what looks like two numbers a six and a four. From the chart the BB was used from 58 - 64 and also was used in 6 cyl power glides, V8 3 speeds and possibly even 6 cyl 3 speeds in 62 - 64. I've been trying to post pic's but just can't seem to get it right. My thought on buying this is to put under my 47 Aero behind a 235 with a T5 trans. I have been looking for an early S10 4x4 but with no luck and I came across this which is the same 60" width.

the casting number 3725899 is for a 1957 car or Corvette

Interesting, and perhaps the cast # 3725888 is actually 3725899. What about the stamped # BB0319? any ideas on that? It seems I'm collecting rear ends, the first was an S10 and it was too narrow @ 54" then I came across the early Chevy and I got it because it's 60" wide the same as the original 47. I'm hesitant to use it because it is so much heavier with a lot of brackets to cut off. Last week I found a S10 4x4 that measures 59" so that is the planed replacement. I'm not sure if this is the right way but my plan is to remove the leaf spring perches off original rear and the S10 and weld the originals to the S10 as I would like to keep the original suspension. I'll also do a front brake conversion to disc.

BB stamping indicated the diff housing was cast in buffalo for a pass car. all 57 corvettes or any c-1's 56-62 were cast in michigan and were stamped AA. if a 57 vet came with non-post, its casting # ends in 899. if the 57 came with post, the casting # ended in 833. but they would have the AA stamping. mike mccagh

Not sure what post and non post refer to as far as my limited knowledge is it meant weather there was a B pillar post or a hard top. It has the stamping BB0319 like I said and a date code C1764. I have since found info that Buffalo castings had two digit year #'s. That makes me think that it was cast March 17th and assembled March 19th. Mike and chevy b, is it possible that Chevy center sections other than 57 vettes, say a 64 chevy car also had casting # 3725899? Is there a list of casting #s? These #'s are hard to read it might be that the last 3 #'s are 833 or 899. Do you know if it was from a 1964 full size car what the casting #'s would be? Oh yea, here is the link to the list of stamped BB letters.

http://www.348-409.com/differential.html#1962-64

Thanks Mike Lenoir

I think Mike meant “posi” for positraction.

Stupid auto-spell wins again!

3725899 was used on all 1957-64 cars and became a parts replacement for 1955-56 cars,

Thank you Gene: as I said I don't know much about these but I'm trying to learn. I have head it is never too late to learn. So I am going with it as a 1964 car cast in Buffalo on March 17th and assembled on March 19th and it having a 3.36 ratio.

Right, C1764 is March 17th, 1964.

What are you doing with this rear end ?

Well I'm not doing nothing with it it's setting outside in the back yard. I've got $300 into it and I would sell it for that. If I don't sell it, it sits. I haven't actually tried to sell it locally yet. There is a FB page , Asheville Hot Rod Swap Meet, I might post it and the two wheel drive S10 rear end on there.