AC's in my chevy's, nothing fancy. I've tried Motorcraft and Champions but AC seem to work the best.
I run the manufactures recommended plug, heat range and gap for the particular engine. I have only been able to get resistor type, maybe non-resistor can be special ordered.
If I convert to an HEI from points I use the same plug but gap it for the distributor. Non-computer GM HEI's use a .045" plug gap. AC plugs can be purchased with .045" gap already set but I check each one before installing them.
If the heads have been changed I make sure the plugs are correct for the new head. Some heads use a tapered seat plug and some use a washer type. I also the check the plug thread depth.
I think the heat range is a trial and error deal. If you run it hard, mainly drag racing, try a colder plug. I believe the recommended heat range is for general useage.
I use to think a tighter gap gave more RPM's but I haven't heard that lately.
My 2 cents!
I run the manufactures recommended plug, heat range and gap for the particular engine. I have only been able to get resistor type, maybe non-resistor can be special ordered.
If I convert to an HEI from points I use the same plug but gap it for the distributor. Non-computer GM HEI's use a .045" plug gap. AC plugs can be purchased with .045" gap already set but I check each one before installing them.
If the heads have been changed I make sure the plugs are correct for the new head. Some heads use a tapered seat plug and some use a washer type. I also the check the plug thread depth.
I think the heat range is a trial and error deal. If you run it hard, mainly drag racing, try a colder plug. I believe the recommended heat range is for general useage.
I use to think a tighter gap gave more RPM's but I haven't heard that lately.
My 2 cents!
