I have an 86 iroc-z with a 1974 350 block swap with an 87 tpi plenium. I have a computer chip for an 87 iroc-z and the differential gears in an 87 are 3.73. I have the stock 86 Differential with 2.73 gear ratio. My question is will this be a problem for my car. by the way it has a stock 86 700r4 4 speed auto.

 

The computer reads off the back of the speedometer so if the speedo drive gears in the transmission are correct and the speedo reads right, should be no real problems. Are you sure the 87 had 3;73 gears? That's unusual unless someone changed the gearing.

 

Jake, if i'm correct you're the guy who's started 4 random threads asking strange questions if they are related to your problem. Like how the rear end gears could effect the strange running of your car.
Try to start a single thread, and give all the info you can. You're really grasping at straws with these ideas.
I'd try going back to one of your other threads, and try to "motivate it" to get more responses.
I'm pretty sure your problem is computer related.