Casting numbers on Rear Differential

[Tony H.]

Did the casting numbers on rear differentials change between 1967 and 1979? How about date formats in those years?

[John H.]

Re: Casting numbers on Rear Differential

Tony -

'67-'75 diff castings were #3899143; not sure about after that.

[Tony H.]

Re: Casting numbers on Rear Differential

Thanks John, I was not sure after 72. So, that helps. Any info on the casting date changes in that time period?

[Joe L.]

Re: Casting numbers on Rear Differential

Tony-----

Casting GM #3899143 was used for Corvette from 1967 right through 1979, the last year for a cast-iron housing on a Corvette. There were no changes that I'm aware of in date coding. However, some of these housings have been seen without date coding. I don't know when these were produced (obviously).