What would I need to change on my 89 iroc to ensure it can handle almost double the hp it has now like brakes suspension.. etc. I have been looking in the forums it seems there's not really to many post of people doing this so i'm not sure where to start. If I go through with it I will be swapping it out with a 5.7 ls3 out of a 2010 ss camaro. My iroc is all stock btw.

 

Brakes - figure LS brake swap as a minimum to sky's-the-limit C5/C6 and 14" rotor options.
10 bolt rear won't last if you get any traction. 12bolt, 9inch or Dana S60.
All rear suspension links: LCAs, panhard, panhard brace, torque arm.
Subframe connectors: inner, outer, or even both.
Strut tower brace.
Make sure anything else that might wear out is replaced or upgraded: steering, and/all bushings, shocks and struts.

 

FYI, LS3 = 6.2L

 

Check out the LSx forum

How do you drive? Clutch dumps and hard launches will require an axle upgrade. Stock suspension with decent bushings is more than adequate. Founders rear kit is inexpensive and adjustable if you have to swap something
3rd gen brakes are flat out scary at 450HP, you'll want something better. Fbody LS1 brakes are a big upgrade, CTS-V/Camaro SS 4 pot brembos are relatively inexpensive big brake upgrades

Not listed, but you'll want to upgrade your fuel system and exhaust, mostly for the swap, but partly for the power