I found a set of D3ve heads that have the AIR passages undrilled. I already have another set that are drilled and already cleaned,taken apart, was going to clean up the exh ports. Is it better to use the undrilled ones? Or will it not make no difference?
On Scott J's site he has tips on how to plug/block off the holes using threaded plugs. You can also use molten aluminum pored into the holes but the threaded plugs are easier. The un-plugged holes can cause some "cross talk" between the ports.