Another small block turbo early valiant

The typical RN12YC Champion converts to a NGK BPR6ES......I was using a hotter
NGK GR5.

I expected to gain 200hp.....so 4 heat ranges colder (to be safe)......

I could have used BPR7ES, or BR8ES, but....

There is no BPR9ES.....at that point the correct plug is the 5671-9 copper.