You will need guide plates if you dont have them already. Best set up is to yank the pressed in studs and goto a screw in stud with the guide plate under it. That is where you get into a bit of head-shop costs. There may be some sort of work-around to get guide plates on your pressed studs, then you could use any aftermarket alluminum roller rocker. If you have the rockers proped up on a guide plate of sorts and not on screwed in studs I would suggest pushrods grow to the added height added by the guide plates to keep your rocker geometry correct. Best is to goto screwed in studs and do it right and be done with it. You may be able to do this on the engine as well. Lets see what the input has to say on the details of getting it done.