spark plugs

[nthdrt]

any ideas on what spark plugs to use on a hobbystock 9-1 motor with 76cc heads? I have a set of 882 and 441 heads

[Dirtman29]

Autolite racing plugs, 5/8" plugs AR12 or AR13, or 13/16" plugs AR72 or AR73, the higher # the hotter the plug. I (think) the 12s & 72s are the coolest temp. wise.

[nthdrt]

whats the differance between a hot or cold plug

[nthdrt]

Thanks dirtman29

[gadirtracer]

Autolite AR133.