Which cylinder heads do you recommend?

Did you drill it with the head still on?? what kind of shape are the heads in otherwise?? you will have to take them off, if it were me I would take it to a machine shop and have the heli coils installed by them, that would maybe be the cheapest, if you get heads out of the junkyard you should have them checked for cracks, your's could be cracked for that matter, no simple solution. it really depends on how much you want to spend. I am sure someone else will chime in.....heres the link to Aerohead: http://www.aeroheadracing.com/id6.html

318 1968-1987 318 A-Engine Heads, 1.88X1.60 Stainless Valves, 67-70cc Open Chamber Design, .509" Lift Springs $399.00
pair