Rob, I tried every spring, jet and rod in the 1407 kit, and some others I had laying around. None of it worked. In fact, most of the time it got worse. Drilling was the only option.
Good luck.
Sorry to say the pic's I had of my ported X heads were lost in a phone problem.
I will say that the porting I had done proved out to be very effective, no hard numbers but there was a big difference in the seat of pants acceleration
Doc if you want those X heads ported I got a Man here in MO that will do them and do them correct. This old Mopar man has ported more heads than he can remember. PM me
Any quality 10W-30 oil that does contains ZDDP.
Valvoline VR-1 is good example, there are many others.
Dont waste your money on additives
Do spend your hard earned money on a good oil filter. I was in the engine industry for close to 40 years and always have used WIX filters. I like the...
Just changing to a AirGap isn't going to buy you much if anything that you can feel by the seat of your pants. Now port the heads you have and port match an AirGap to the freshly ported heads now your going places and you will feel the difference.
With no oiling mods I went from using a stock oil pump to a Melling HV pump
Oiling thru the shafts, roller rockers and pressure feed roller wheels.
Hot idle oil pressure, in gear, with the standard oil pump was 15 to 20 psi, with the HV it is now 25-30 psi