Well fix the mechanical issue 1st. Like spring pressure and check the valve to guide clearance. Give NGK a call for the plugs as they were bang on for my race motor. Keep us posted as Im interested in your results.
Already have the heads rebuilt. Chamber is completely fixed and within 1/2 cc of other chambers, have Engine Pro Racing black nitride valves and 155# springs. I ended up going with NGK 8s. Should be back on the road soon.
Mallory 685 box banged the hell out of my blower when it smoked! I have it mounted inside the car and I couldn't even touch it it was so hot! GRRRRRR. No damage luckily because I was at cruise RPM. I bypassed it and got home.