Nitrous Oxide - Spark plugs for brodix heads?

I have a set of brodix heads and I'm having problems trying to find the right spark plug charts. On their sight the plugs that are listed to fit these heads are Autolite 51 or NGK B9ES. Does some one have access to a chart that breaks them down into heat ranges. I want to know what plugs I'm going to have to run in these heads for shots of nitrous running from 150 shot up to a 350 hit.

Thanks for the help :confused:

The top sticky post #7.

I may be wrong but I don't think these heads use the same plugs as a LT1 or LS1

thanks

These are converted Brodix -10 heads anyone