spark plug guide
 

Ok I know this is a stupid question. Who has or how to go about getting the correct spark plugs for the application?
I have a customers bbc corvette with a 502 BBC with ported world products heads. I have a set of plugs that came out of it but don't know if they are correct. I understand how toi determine heat range etc but is there not some deal with plug depth etc?
Also am I supposed to use resostor plugs with resistor wires?
Al

NO resister plugs with resister wires!

We run the ngk's plugs in our 496 merlin headed bbc part # 5673 in the number 8 heat range.
$!.99 per plug at napa auto parts.
Goodluck, Charles

Is the NGK 5673 plug a .460 thread reach plug?And will this plug work in BBC990 heads.They have Autolite 133's in them now.Just trying to find the correct plug also.