Well, I've always read the safe limit on the low deck factory block is around 650 horsepower. And that's possible with some TF 240 heads and a SFT cam. If I were to go over to bushed lifters, the expense of a solid roller, and max wedge heads then I would rather put all that down n the stronger, raised RB blocks that can achieve a 4.5 inch bore. It would be a rather nasty street engine.
