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posi in my 78 camaro

1K views 1 reply 2 participants last post by  diver 
#1 ·
I'm looking for some help with something...i have a 78 camaro w/ rear axle code PJ---2.41:1 RATIO....I KNOW, I KNOW IT'S PRETTY SAD!! i want to get a 3.42:1 ring and pinion set and get a posi carrier...just not sure which one would be best. i need more pickup, but would like to be able to cruise w/out being at 6 grand....any help would be appreciated
 
#2 · (Edited)
good choice

3.42's are a common gearset for a late model chevy with an automatic with an overdrive. It is a cruise RPM of 2500 at 75MPH. I have this same set up. BUT, if you have a turbo 350 with no OD, then you need to do some serious checking. If you look around there are some gear calculators on the web for free. You plug in the rear tire size "height" and then you tranny final drive ratio which a T350 is 1.1-1 and a 700R4 is .070 and the RPM you want to cruise down the highway. Like my Pro Street S-10 has a 1-1 and I have 31" MT tires on the rear. A 3.42 gear set puts me right around 2800 @ 70 MPH.

Go here: http://www.classictruckshop.com/garage/shopmathrpm1.asp
 
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