People say that you only really need the 2 bolt and it will handle like 900hp+. is there really a need for a 4 bolt conversion?

 

The LT1 is pretty strong. For piece of mind, though, I would start thinking about 4 bolt mains at around 450 hp. A lot depends on how the engine is treated. A little more strength can never hurt.

 

It's also possible to take a 2 bolt main and drill and tap it to make a 4 bolt splayed main where the two outside bolts screw in at an angle for extra strength moreso than a regular 4 bolt main, something like this \ |O| / looking at the engine upright.

 

I asked a little while back and I was told I would be alright with my power and two bolt mains. It is NA though...Any sort of stroker + power adder combination I would do 4 bolt mains do doubt.