OK, so I have an '87 roller motor in my '66 GT that was built with a flat tappet cam....don't ask why, I have no idea. Well, the flat tappet cam now has one lobe that's wiped-off. I want to go back to a roller cam that I spec'd through Comp Cams. Engine has World Products Windsor Jr. heads that I've been really happy with. The question: I know I will be changing out valve springs, but can I sneak the roller lifters into their bores without pulling the heads?....Looks pretty tight on the end cylinders just eyeballing it. If I have to pull the heads, then I'll just pull the motor and call it a winter project. If not, I'll just remove the shock tower supports and work on engine in the vehicle. Opinions welcome! Thanks for help on this. GT1966