Pete,
After you wiped out the main bearing how did you fix it so it did not repeat. With most performance motors I normal direct feed the cam with oil but I have not run into the crank itself starving. Do you just drill out the crank? Increase the pressure/volume?

 

Increased bearing clearance 0.0025, higher oil pressure, opened up the crank oil passages, chamfered the holes, and used straight 40W Red Line oil. The problem is the oiling system on the 3.4 is poorly designed, even after the factory upgrades in 1994. The ideal solution would be to use a transverse engine block, which has a much better oiling system and supports the use of roller lifters, which the rear drive 3.4 does not. However; a lot of fabrication is needed to mount the transverse engine in a Camaro, as there are no provisions for motor mounts on the side of the block.

 

I don't plan on a turbo or anything like that, just heads, headers, CAI, and cat-back. Are there any major precautions I must take before doing any of those to prevent failure?

Also, heads from a 3600 engine would also bolt right up to the 3.4 block?

 

The heads will bolt right up, but the compression will be very high, so get a long duration cam to blow off some of the compression at low RPM. Also make sure to get the rocker arms that go with the heads. The heads use canted valves for better breathing and unique roller rockers.