Forged Crank Swap

I have to rebuild my shortblock on my 91 Stealth R/T NA. I want to put a forged crank and pistons in it instead. Is this a direct bolt-on or do I have to 'modify" (aka 'redneck') some parts to do it??? Or do I have to buy a 4-bolt block to do it?? I want to know what I am getting into before I actually start down a path that could cost me more than anticipated.

its a dirrect swap. the only place you can even get a cast crank for this engine is used, they arent made anymore.