72-76 351w blocks, how much Hp can they hold?

The blocks going to have main studs, main girdle, and head studs.
I am geting a superchrger, so i need to know whats safe is 750 fwhp to much to ask , i know mike star is putting out 900+ but thats on a race car/strip car, i need to know the max hp that will be safe for a car that is drivin 2-3 times a week, sometime less, useuly 2-5 hour crusies/ just havein fun , this is going in a play around car but dont want to blow it up.
after 3-4 years ill finly buy that 351w Dart Block and up it to 1000+ hp

ttt