i can not help you much as i never used this head as it not to ez to find and theres still some 049 /781 that i rework and new iron and alum heads so thats the way i go .i can tell you that you will have to rework your deck to use the new head with a new head gasket . not a big deal fel pro put s it in there head gaskets is a chart for just drilling some holes in the deck .i do this on all the big block s. i done it this way for over 15 years hard to say it may help so it gets done . but if you use a mark 5/6 head gaskets and you will then it must be done get any hot spots out of the head as the coolent moves thru the head .all bbc are 1.7 rocker if the heads are re work and have good flow as i here they do i would use more the 544 lift about 620 ersons makes some hyd roller s that this lift i use that seam to work good . as for the 500 hp thats abit but it could be done with the right parts