Whats the best spark plug for a turbo charged 5.4 with 8psi, pump gas, stock coils and 8.5-1 compression. I figured on using the stock Lightning plug but which brand and at what gap? Also what I know as I up the boost I will need a colder plug, coils & msd stacker. So if you could give me the brand names, part number and heat range(stock, 1 step colder ect...) I would greatly appreciate it.

 

With that amount of boost and compression the NGK TR6 would be fine for that. The L boys love that plug.

 

autolite 103

 

I just bought XP103, what gap do think I should run with stock coils and 8psi boost, also should I change the gap once I get new coils and MSD stacker?

 

stock 35 gap should be fine for 8lbs.