Recently built a 406 sbc. I ended up getting a nitrous kit for a song after I built it and am debating on whether the motor will hold up or not. I would re-gap the rings but my main concern is the stock crankshaft. Will it hold up or not. Its approx HP is 450 and ft lbs of trq. I-Beam push rods. If I'm pulling the pistons to re-gap the rings I will change over to a forged piston but will the crank hold up to a 150 shot. Thats pushing 600 hp when its all said and done.