It can be done if you have the budget. Just remember all the supporting mods that need to be done. Transmission, rear end and you'll probably want to upgrade the brakes too. 400RWHP is good for low 11's - high 10's with a good suspension. That means a roll bar, power adder means you need a fire jacket too. And with that much HP you WILL need the good rods and crank. And a good tune or you'll crack the block in half.

 

hmm... what do you think a 331 with gt40P heads and a good cam with the blower may make as far as power? i want a blower but i dont really wanna split the block lol
and i have a 9in that;ll get narrowed soon and im workin on getting a toploader. and i am getting 4piston wilwoods atleast up front if not all around. i dont NEED 400 to the wheels, just a dream but like 3-375 wouldnt hurt more realisticly speaking as i am trying to keep the cost somewhat low as in i dont want to spend 8k on the motor

 

gt40 and gt40p's will be restrictive for a blower imho.

 

You could do it with the P and GT40 heads but you might want to just look for some aluminum heads. They're going to make more HP and help keep things cool and avoid detonation. Personally, I'd use a later 5.0, stock crank with good rods and pistons. Add a custom cam designed for a blower and a set of AFR 185 or similar heads. 7-8 PSI and I think you'd be there.