Can anyone tell me the correct factory installed plugs for a 70 Chevelle SS LS-6 (head cast #3964291). Can't find AC part number anywhere.

Thanks, graemlins/beers.gif

71 Chevelle Malibu
454 LS-6
turbo 400

My 1991 AC Delco spark plug book says "454(LS6 Only)" using either a AC R43XL or AC R43XLS plug. Thats if your heads use gasketed plugs. I would use the AC R43XLS (extended tip).