I agree, go with the 9". I have one in my '64 GTO, built by Currie. It has all stock Ford parts in it (Detroit Locker, 31-spline axles). I run it with a moderately-built 400-horse 455 attached to a transbraked TH400.
10 years of racing with slicks and no failures. I don't have the most powerful engine (car runs 12.0s), but having a reliable drivetrain is a real blessing. I think for a few more $$ the 9" will be the best choice.
My bracket car.
The rear was custom-narrowed to fit my 10X28" slicks, no wheelwell mods.
