The folks at Race parts Dist. here in NC suggested to me that if I was going to build the 393 to go with the Edelbrock Victor jr. heads and the Victor jr. intake, which I did. These heads are probably as good as anyone's for street/strip/road course applications. Along with TFS and Edelbrock, you can also do real well with Brodix track 1, and Air flow Specialities 185 or 205 heads. My Edelbrock heads have 2.05 intakes and I don't see how you can get any bigger without doing some major mods to the valve geometry. I believe that Brodix has changed the geometry a bit to get large intake valves into their heads. They do require the use of the offset rocker arms from Ford. But you can go on forever, the possibilities are endless with all the heads, cams, and carbs available. Have fun
h dog