[Torx]

i got a set of 22s, the tires and rims total at a 29" diameter

how would i calculate what rear end gears i would need to safely drive right without damaging other stuff like trans and overworking the engine?

what factors do i need set in stone before attempting a gear swap?
and do i need to convert to a ford 9" or somthing or can i keep my current g-body gm rearend?

[Jishory]

well it depends, what size of tires did you have before? you can get gears for any axle

you can figure how hard it will be working the engine by the ratio of the old ring and pinion to the new. say your engine runs at 5000rpm when your going 100mph for the sake of easy math. you have 3.55 gears and want 4.10's so you figure 3.55 x ... found this easier: http://www.ringpinion.com/content/calculators/RPM.asp

[81 Elcamino]

well with a g-body im almost positive that the best gear you could hope for would be 342's or 308's, but they get much worse ...

you can use the guts from an s10,blazer and it will fit your current rear end my brother has 410s's in his

[offroadin]

Basically you can do it simply with percentages.

Say you take your new tire overall diameter (29") and divide it by the old tire diameter say 25"????

29/25 = 1.16

Now your stock gear ratio is probably something like 2.73 or possibly 3.08s since you have a 6 cyl.

For the sake of calculations we'll use 3.08s.

X = corrected gear ratio

So you take X/3.08 = 1.16

so X = 1.16(3.0

X = 3.57

Now Your rear end I'm assuming is the standard GM 7 5/8". THe closest gear ratio available to 3.57 is probably going to be 3.42s. But if you want to correct the ratio and gain a little more jump off the line (better acceleration) I'd go to something like 3.73s.

Keep in mind that the higher the ratio the higher RPM you will have to run to maintain cruising speeds on the highway.

[Torx]

great info guys!

i'll do my own little calculation after work and see if it will match up to 3.73 or 410 or 342

where would i buy the gears from?

think i should drop a new engine and trans in before changing gears?

[offroadin]

A bigger engine with more torque will help turn those tires a lot nicer, not absolutely but if your engine needs replacing, it wouldn't hurt to go up to a 350 (don't bother with a 305 same gas mileage as a 350 with less balls).

Your tranny is auto right? It's probably a turbo 350 or more likely a 200-4R (if it is an overdrive - Turbo 350 is only a 3 spd)

I won't bother with the tranny other than maybe adding a auxiliary tranny cooler.

As for gears, any mechanic shop can get them and install them for you. It requires some special tools and know how. THe backlash and pinion depth have to be adjusted properly or the new gears will wear out prematurely.

[Jishory]

engine swaps are a huge fucking pain dont bother