I have a 1988 camaro iroc z that governs at 100 and i have a small CAM and 373 posi-trac lots of low end but no high end torque just put NEW tranny with shift kit and forged racing pistons im pretty sure i can go faster than 100 but ive never done it

 

If your IROC came stock with 15" wheels and non-speed rated tires the speed was limited by the Prom in the ECM. You will need a new Prom (chip) to remove the governed top speed.

 

I think you're confusing the governor on your trans with the governor on your go-kart engine. The transmission's governor isn't a car speed limiter. It controls where the trans shifts points are compared to engine RPM. The governor can be modified by changing the springs and weights, which you may want to do anyway since you went with a lower rear gear.
And as blackz said, your speed would be limited by the ECM. If you never plan on going 100, I wouldn't worry about it. But, after you changed gears, did you fix your speedo so that it reads accurately again?

 

well the guy i got it from told me about the mods i didnt actually put them in myself. and yes my speedo is about thrity miles an hour fast. any i dea on how to fix that

 

the wheels on my iroc are 16" iroc rimsnow whether or not they're the same stock wheels that came on the car i dont know. but i also noticed some body work on the car and my key for the driver door doesnt work on the pasenger side or the hatch but does work for both t-tops

 

30 mph is A LOT!!!! To be off that is. Must have been a drastic gear change.
Go to Kiesler's trans site or Classic Chevy trans site and they will show or tell you where to find a mph calculator on line.
Sly