Bearings

I was talking my buddy who is familiar with the 4.3 and he has certified with chevy, He said before I do anything like , cammy , pistons , etc to swap out my bearings because the stock ones are junk and i will blow out my bottom end. Does it sound worth it to do it ? Would i have a big performance gain by swaping out all internals ?

changing out your Rod and Main bearings will only help extend the life of your piston rods and crank. You wont get any HP gains at all.
 
Now if you rebuild the engine and bore it, put in larger pistons, longer piston rods, larger crank, Port and Polish the Heads and Intake, then you will get some HP gains. But would be cheaper to do an engine swap to a 350.

Thats what i was wondering. Thanks