Built a ’53 flathead ford using your .400 finned aluminum heads and a 2 deuces intake . Other than a Isky MAX-1 cam and solid lifters, and a .040 over bore, everything else is stock (ie crank, rods, etc). It does have a Mallory dual point distributor. What heat range should I be using. Stock calls for Champion H10 plugs. They seem to be a bit cool for this application. Am I correct? Thanks for the help.