I have a 1969 Firebird with a 428 that was built up by the previous owner. The engine was originally in a Grand Prix but was bored and built to be a drag racer. The spark plugs I have it in now are AC Delco R44S but they no longer make this plug. The plugs are very fouled and need to be changed.
Most auto part sites recommend the AC R43S for this engine but I'm afraid this plug may run too cool for a built-up 428 engine. Any suggestions on a good plug to use for this car? The car will only be used for street cruisin' and will no longer drag race.
The previous owner supplied me with the below specs:
1969 Firebird Specs: 1968 428 4 bolt 40 over TRW pistons 58-62 Forged rods RPM Limit 6200 430 Chrysler rear Cylinder heads #16 Valve screw in studs Poly locks Ultradyne 288-296 cam Street dominator mid-rise manifold Holley 750 double pumper
