okay, so my car is an 85' z/28 coup with a swap to a TPI 5.7 with an errson cam. 290 duration .310 lift so i open at .465.

so atm i have NO idea what my stock rear is(going to have to take the cover of to see) but it should be a 3.23 according to tech data. SO, my goal is to help get some more traction. I am looking at an Eaton Posi rear carrier with richmond gears. I also might get a 2400 stall converter to go with the whole package.

Now my question is, what would be better ratio? 3.42 or 3.73, I street/strip the car. and I run a 14.6@93 but my main problem is TRACTION! it kills me, my 60ft time is terrible because all i do is spin(open rear)

I also want to know kind of effect higher gears wil have on my MPG, im not terribly worried just a curiosity of mine.

so cliff notes: what would be the best gear ratio for me?

 

probably cheaper to just buy a used posi rear and swap it in IMO. No sense dumping $700-1000 into a gear swap and posi added when you're half the price to a 9" swap then.

 

The 3.42 will probably have little effect on the fuel mileage. You know that you have the small 26 spline axles, right?

 

I dont know, according to data i do but i really need to take tht cover off and look because I cant read anything on it and the numbers I do have wont tell me anything