I had my already ported heads sent to Champion to be redone with new valves, valve seals, etc......I was told by Tom that they take the same amount of material out of a set of heads.....He told me mine were opened up more than what they open there heads up too......When I asked why they port them all the same amount he said in the early days through trial and error some sets could be opened up bigger than others....They would take another set try to port out the same amount and bore through a water passage....They settled on a specific amount to port and stuck with it as too not ruin any heads......I'm sure many have successfully done this including Tom himself , but I would bet if the car doesn't make some good power the gains would be minimal???
the champs irons have a nice port and polish as is out of the box , compared to heads Im running with stock runners the champs are a huge improvement .
doubt youll improve on their current cnc program without tubing the pushrod holes for the 3 and 4 intake , its just not needed for 9s
bigger isnt always better, id rather know they were ported for even flow even if that meant they all should be smaller
if you go champion either get them with comp/manley PC seals or change them before you bolt them up , the teflon valve seals they use always seem to hang up on the valve