Contact the cam manufacturer you like for specifics, but most of the high end solid flat tappets are made from a different core, not regular cast or ductile iron. Key is how hard you want to run it and how much lift you want. You will not get the equivalent lift for a given duration in a flat tappet. But, no reason to go to a roller unless you want the added lift. Your AFR's are supposed to like a lot of lift. JMHO, but in the application you are looking at, it's only a few hundred dollars difference to got to a solid roller as compared to a high end solid.