With the Pertronix FlameThrower coil, Pertronix wires, and Pertronix Ignitor in my son's car, we ran a gap of .040. The plugs would last about 2k miles and then were toast. Tried it twice before setting them back to the stock .036 and never had another problem.
Now if you're running an MSD6A type box, I think it's different. With an MSD billet distributor, MSD 8mm wires, Blaster II coil, and MSD6A-L, I run a gap on my '66 of .051
Personally, I couldn't tell any difference at all in running the .036 and .040 in my son's car, other than the plugs would last longer.
Now if you're running an MSD6A type box, I think it's different. With an MSD billet distributor, MSD 8mm wires, Blaster II coil, and MSD6A-L, I run a gap on my '66 of .051
Personally, I couldn't tell any difference at all in running the .036 and .040 in my son's car, other than the plugs would last longer.