20 psi is perfectly fine on an LS, even for a stock bottom end never been apart engine. A lot of times people will drop the pistons out and regap the rings for boost and then reinstall. But even untouched they respond very well to forced induction. As long as your tune-up is properly set for it and you don't have some kind of mechanical failure then it is a perfectly safe number. I like having more in reserve if i need it. I like that i wont have to push this one as hard as i did the last one because it makes just over 200 more whp at the same 20psi as my 370" LS.