It's been many years since I went down this road,but as I recall it takes an effort even with .100long sbc valves to get enough installed height to find a spring that is functional. You may also need to run 1.5 rockers,another option would be a different camshaft as the one you've got is more than needed. Sorry I just thought of another problem,what are you going to do about those tiny 5/16" rocker stud bases. I don't think they would live well with the combo you have. They can be drilled and tapped for 3/8" and I've gone so far as to use 7/16" studs,but the meat around the stud gets pretty thin. For an 11 second combo you might want to keep it simple an use a milder cam/spring combo.