My friend has an 89 IROC that he just got a new engine put into. The engine is a new 350 longblock from carquest. It is still tuned port injected and has headers and a straight 3" exhaust (no cat just muffler). I drove it before the first engine was blown, but now it has not anywhere near the power. The torque seems lower and it definetely isn't the same. The temperature is constantly on 220 (he has a 160 thermostat) and the engine was professionally installed at a auto shop. What could cause this problem? Did the shop screw up? Or is carquest a big rip off?

 

Probably not a rip off, just not a comparable engine to the L98 he originally had.

Probably lower compression (heads) and a different cam.

 

CHeck the ignition timing. I've heard of people putting in cheap parts store replacement 350s and they might not be as good as the L-98 was but generally the results are not that bad.

Running hot + no power = timing retarded (in my book anyway)

You MUST disconnect the timing wire above the heater box before attempting to adjust the timing or you will end up with the timing retarded about 10* from where it should be. Stock setting with timing wire disconnected is 6* BTDC, but you can easily bump it up to 8-10* BTDC for a little more power.