i am building a 500 stroker,4sd, 3:54, 440 in a 69 gtx. i see the performer rpm is not going to fit under my hood, i have a air grabber, but would delete it if it would fit? what manifold would you suggest to get the most hp? stealth heads, trying to keep stock looking, and around 550-600 hp range. may not be attainable with intake? thanks for input.