I bought a 68 chevelle 4 months ago,that i've been working on .and i finally have gotten it out of the garage. my chevelle has a 355 engine w/a turbo 400 trans,and a 1980's camaro rear.which for some reason,he welded a plate over the diff.cover.so i cant readily figure out the ratio. the best that i can do,is tell you that it tachs 3000 rpms in drive gear(3RD) at 60 mph.i hope some can give me an idea what ratio this,I would appeciate it. thanks. sasquatch58

From your tach reading I'd sy you are somewhere in the 3.90 range - but an easy way to tell, if it's not a posi, is to jack up one rear tire, mark it, and make two complete revolutions with it while you or an accomplice counts the drive shaft revolutions - four turns of the drive shaft would equate to approximately 4.0 to 1. If it's a posi, get both rear wheels off the ground and do the same thing - only turn the wheel just one turn.

however, with the converter slip.. it wouldnt be accurate... i would jack the rear up to find your ratio

Originally posted by OzarkBowTie:
From your tach reading I'd sy you are somewhere in the 3.90 range - but an easy way to tell, if it's not a posi, is to jack up one rear tire, mark it, and make two complete revolutions with it while you or an accomplice counts the drive shaft revolutions - four turns of the drive shaft would equate to approximately 4.0 to 1. If it's a posi, get both rear wheels off the ground and do the same thing - only turn the wheel just one turn. graemlins/thumbsup.gif