i have an 89 iroc with the borgwarner rearend option i plan to use small slicks i was wondering how it will hold up i should be making around 400 hp at the flywheel thanks

Jason , the 1989 Chevrolet IROC had an engine rated at 190 hp . Figuring the usual drive train loss , you might have had 160 hp at the rear wheels . Remember this was when the car was new . You didn't say if you bought the car new and being that the car is now 20 years old and not knowing the history if you didn't buy it new , you really don't know the condition of the rear end ? You put 400 hp to it and you'll find out quickly it's condition . The unwritten rule in this is - when you upgrade the engine , count on having to upgrade the transmission as well . It only makes sense that the rear end would be the next thing that would need an upgrade . Also , most people totally forget what is probably the biggest need that should be addressed in a situation like this . That would be the brakes ! So you see what a " Domino Effect " is created when you go down this road ? There's nothing wrong with what you want to do to your Camaro - we've all done it ! You just need to look at the big picture and be aware of the possible pitfalls . Good luck and keep us informed of your progress !

the trany is sound and i already assume the worst for everything else the car came factory with 4 wheeel disc brakes and i plan to to drilled and vented rotors i am aware of these things i just wondered iff someone had put this much power to the stock rear end

if it's the 9-bolt it will probably be ok.