Hey all, heres a scenario for ya. Ya just got an 89 IROC-Z a couple months ago. It has the automatic 700R4 transmission. The tranny is behind a 350 engine (if that makes a difference). The transmission (along with the engine) has 108,000 miles on it! It shifts just fine, it shifts at the correct times, all gears work. Its in good condition, although there is a leak at the tail seal, but very minimal. And the rear differential for that matter also has 108,000 miles on it, with the 2.77 gears 9 bolt. Now... what be your future plans for the tranny (and differential)? What would you DO to it? What would you NOT DO to it?

 

Put a TransGo shift kit in it so that the shifts are a little quicker and firmer. And then a 2200 rpm torque converter so you can blast off the line like a banshee

Then, if that didn't take all you money, a set of 3.23 or 3.42 rear gears and posi.

These three mods should knock a full second off your ET.

Mmm, mmm, good!