My PRW 1.6 rockers hit the retainer on my ProMaxx heads and I'm sure they would on the TF, but the B3 shim kit will take care of that with no grinding on the parts. That interference is apparently very common in aftermarket rockers, regardless of the head used. When the spring diameter increases and all the other aftermarket nuances that occur, something is going to get in the way. That's why it's called Hot Rodding. It's making it work that is half the fun. If you want Lego's that fall together, this is the wrong hobby.