Vman73 said: Hey Mike, I don't have a quick reference to the diff casting number you posted above, I'll do some digging. The casting date B249 does decode to Feb. 24th 1969 which is perfect for your March '69 car if I'm remembering your build date correctly. Though it might be too late since you have the diff installed, there is another casting date for the diff rear cover. It's located in the vertical position just above and forward of the fill plug. Your cover is probably original, but many got replaced because the ears that the spring bolt to like to break off. A lot of covers also got replaced with a stronger aftermarket casting with a larger flange that prevented the problem. Looks great !!

Thanks!

The car has a July build month I believe.