8.75 What do you think?

[JVMopar]

Unfortunately I'm building a wissota class street stock car for my College Senior Project. Well it's gonna be a '86 Monte Carlo. I'm gonna use a 8.75 out of a 71-74 b-body. It's a 489 axle. Well I'd like to know how big of gears will fit in that carrier. The typical gear is 6.00 through 6.50's. So what do you think?

[Stoga]

Well, I don't see much chance of you breaking one, with a small block chevy, especially in that application. But you may have a problem finding the gear ratios you want for an 8 3/4 differential.
The highest,(lowest?), gear ratio in the Mopar Chassis book for a 489 case is 5.38:1 ratio, part number is P4529916.
The only other gear ratio in the Chassis book that even comes close is P4529926 6.17:1 for a Dana 60 rear end. Unless you can find the ratios you want from an aftermarket supplier, you may have to go with a Ford 9 inch, thus driving up expenses. Maybe you could juggle transmission ratios, or change which gear you plan to race in,if you're running a 3 or 4 speed manual, but it just doesn't look like Mopar makes ratios of that nature for an 8 3/4. Cross your fingers and check the aftermarket, good luck! As ever, if anyone else knows of a source or has more info, please jump in here!