Sean James
Member
Whoa! slow down. Adjust the rocker arms, before you do anything. Aluminum heads? Different pushrods? Who knows? I had the same exact issue with just a cam change, and it turned out to be the rocker adjustment. Unless you have tried that already, sorry for the post. I rebuilt my second small-block back in the 90's, Edlebrock internals, Holley externals, all the good stuff back then. After around 800 or so miles everything went to shit. It was the damn rockers backed off. I thought it was the studs pulling off the new aluminum heads. Nope, it was the rocker arm nuts backing out. A Vacuum gauge will tell, but even then if you have a big cam, it can lie to you. Had to get locking rocker nuts. Just a thought, it does happen. YouTube is your friend on how to adjust SBC rocker arms.