Spark Plug Heat Range

I am currently running Autolite 66 plugs in my 8.5:1 318, .030" over. The cam is a Comp XE268 (.477/.480 lift) and using an Edelbrock Performer intake. The carb is an Edelbrock 1405 600 cfm. Hooker headers and a MP quick advance distributor with 18 degrees initial.

Would you guys continue to use this plug, or use a different heat range. If so, which? Different plug brand?

How are the Autolites doing for you? If they work and look OK they are a decent plug. If you want to try something different, I've had good results with NKG's using Mancini's guidelines based on compression ratio. See attached link.


http://chucker54.stores.yahoo.net/ngkplugs.html

NGK's.

Would a Autolite 64 or 65 be a colder plug? Mine seem to be tad warm running, judging by the whiter tips and electrodes rather than brownish. Maybe I need a slightly cooler plug? Carb mix is ok.

I am not an expert but I thought the 65's were cooler than the 66's. If someone knows for sure I am all ears. Best regards.