You have to run hardened pushrods with guideplates (stud mounted rockers). I got the TFS heads because of three major factors. First was price. They're definitely cheaper than AFR heads. Second was the ability to run a 2.02 intake valve. Try that with some AFR's (185cc model. 165cc heads run a 1.94 intake valve) and you'll end up with some severe piston to valve clearance issues. TFS gets away with it because they use canted valves instead of inline like the other manufacturers (Edelbrock, FRPP, AFR, etc.). The third was mainly just availability. Of the places that actually had the AFR heads in stock, some of which I had never heard of, I just didn't feel comfortable ordering them. I went on Summit Racing's website and ordered a pair. No BSing around, no searching for the best deal on the overpriced AFR heads, just click and wait a couple days for them to arrive.