which gears and posi

[Ishmael]

To start, my father-in-law has a 2000 vette with around 400 hp, otherwise stock stick convertible. I need to go faster at least in a straight line. My 68 firebird is on 18s, I plan on putting a 200r4 in it (is it the same as a 4l60?). What I need to know is what gears should I put in that will allow me (horsepower gods willing) to go toe to toe with him while not killing me on the highway. As well which posi unit should I go with? I was thinking an eaton posi or eaton detroit truetrac or should I just go with a stock gm 8.5 posi. I've been reading they can take all kinds of abuse. This car will only see the odd 1/4 mile and stay mostly on the street.
thanks guys
Scott

[big gear head]

What rear end is in your car? If it's stock then it will be the BOP 8.2 10 bolt. This isn't the best rear end, but it isn't all that bad either. Parts are more expensive for it and harder to find.

A 3.42 or 3.73 would work pretty well with the overdrive transmission.

[Ishmael]

There was an 8.2 pontiac in it but it isn't going back in. Thanks for the gear ratio suggestions - I guess I just wanted to hear someone else say it. Any suggestions as to a posi unit?

[Scott Parkhurst]

TruTrac. No clutches to wear out, gradual engagement around corners, and brutally strong. Best of all worlds. I'll never run anything else, and I've run 'em all.

[big gear head]

If you are going to use the 8.5 corporate rear end then the Eaton Posi is a very good choice. If you want to do some auto cross or road racing then the Truetrac is a good choice. If you are not using the 8.5 then your choices might be different. Some rear ends are limited to what is available for them.

[Ishmael]

Thought I had a nova 8.5 - turned out different. I'm still looking. In the meantime the pontiac 8.2 is looking like it might go back in. I'll see if the truetrac is available for it.