I have been wanting to throw in some 3.42's now and I have done some research. I want a bullitproof posi unit and some gears. Now some people say that gears will decrease my 1/4 time, and some do not. Will the swap from open 3.08 to posi 3.42 do anything for me.

Also guys does anybody make a 28 spline posi besides Auburn Gear?

Reason I have this in TBI boards is because I have been told our TBI cars react different than others.

 

I'd go eaton for posi, I'm about 90% sure they make what fits your car. With 3.42s you will at least see an improvement in 60' times and probably 1/8th mile times but it depends on your power band if they'll help in the 1/4

 

eaton posi is the way to go plus if you do the swap without fixing your speed-o it will read wrong and cut you off at what the car thinks is 110 mph.
i resently swaped my 2.73 open diff to a 3.45 posi 9 bolt and my speed-o is about 15 mph off so my speed limiter cuts me off at like 95