Hello there,

Sorry I know this subject has been beat to death, but I’m still confused about posi & rear end ratios. I understand the concept of both wheels spinning for the posi as opposed to just one for the open drive. However, I’ve heard two different things about them which concerns me. Particularly about cornering, I’ve heard posi will lock up and spin you out if you corner and I’ve heard it does better because it allows one wheel to travel slower than the other giving the car more “grip”.

I am putting together a T Bucket, and am working on the rear end now. So far I’ve got the 9” Ford rear end housing and have been told all sorts of advice and not been able to make sense of it all yet. I’m running a 350 SBC (bored .30 over) backed by a Powerglide transmission. I don’t have the back wheels but my rims are 15x15 which I *think* will need 31” tall tires.

The car is not for racing, just driving around occasionally. I was told that with such wide tires, I would flop the car over if I didn’t run a posi. Then I was told by someone else a posi would lock up on me and could spin me out if I were cornering. I’m sure it all comes down to how you drive, but I want to make sure.

One last thing, about the ratio, I was trying to do the formula suggested but I have no idea what RPM my engine would be at while doing 60MPH. How do you find out without running the engine? (I’m feeling really dumb right now!)

If anyone could clear that up, I’d so appreciate it! Thanks!
-Jackie