I have the oppurtunity to purchase a T56 and a posi disc rear off of a 1995 Trans am for $800. I was told that both these units have 70,000 miles and are in good condition. I was wondering how much power this combo will hold. I plan on building a 383, i want to take it to the track but i wont be beating on it on the street. Is there a way to visually check the condition of parts, i can look at the odometer and see the mileage but mileage isnt always a good indicator on condition... Please let me know, i appriciate all the info this site has given to me.
Thanks,
Dennis

The T-56 will hold a bit more HP than say a T-5, but the rear is the same basic unit used in the 3rd gen cars so you will want to watch the HP launches , there isin't a good way to inspect the trans without taking it apart but you should be bale to drain some fluid to inspect it for color and metal particles ..

Thanks, i have the oppurtunity to buy the trans for $500 so maybe i will just do that... what are the advantages of a 4th gen rear if not for more powerful launches...

They have nicer brakes (if they are disc) but internally they are pretty close to the third gen rears and the cases arent any stronger + theres the issue of them being wider than the 3rd gen rear which makes it harder to fit rims...