well i planned on running a twin turbo setup through a holley sniper, and by forged internals i mean all the works this is going to be a drag motor going into a 95 pontiac firebird formulaDepends on the what “forged internals” really is meant by you. Pistons, better rods, crankshaft and main bearing caps are the typical replacement items when adding boost at competitive levels. Normal street boost is 6 to 10 psi. More than that takes a pretty fancy set up.
Assuming by boost you mean some form of super charge rather than nitrous.
Life span of the block goes down as the power goes up. Additionally, how you use that power counts occasionally on the street can be reasonably long time, in competition the life span gets consumed pretty quickly. So in the end any useful comment needs some understanding of what your doing with and to this motor.