I have been searching CF and internet to find out the correct spark plug heat range for my engine, but not having much luck.
My engine is 383ci with 10:1CR and aluminium heads and almost stock HEI with upgraded high voltage chip.http://www.ecklerscorvette.com/corve...1975-1980.html
I have bought these spark plugs but am not sure if the heat range 4 is little too hot?
NGK heat range goes from 10(cold) to 1 (hot)
What heat range would you recommend for the initial starting point?
I would like to stay with NGK product as it is easily accessible in the UK