Hi, this is my first post here but i was looking for some opinions, i have an 86 Trans Am that i picked up not too long ago with a spun rod bearing, and half way through rebuilding the 69 327 that was in it, i got an amazing deal on an 88 IROC, 67,000 km's, completely mint condition inside and out, and 100% stock, but it has the 305 tbi and a 5 speed, rear drum brakes as well, i'm not sure what rear end is in it but i know it's not posi, but the t/a has the bw posi 2.77 rear end w/4 wheel disc.

i'm just looking for some opinions, should i just stay with what is in the IROC and keep it original? is it a real pain of a swap? and is that t/a rear end a pretty good choice or should i be looking for something different to stick behind the iroc?

 

Your 5-speed has a 2.95:1 first gear. That's not a very good match to a 2.77:1 axle. It can be done, but you probably won't like it. Right now, neither engine is strong enough to break either axle, unless you try nitrous and drag tires. The '88 probably has 3.45:1 gears in the axle, if it's original, and a 0.73:1 fifth.