to elaborate on my above post something does not add up or i misunderstood?
there are many calculators on line but here are two i use:
http://www.sccoa.com/faq/tirecalc.html
http://www.corvetteactioncenter.com/...s/rearend.html
those coupled with this chart and you see that your tire height with that trans and rear does not equal 3200rpm. maybe trans speedo gear is wrong one?