Finally getting rebuilt engines together. After having carb issues and fouling plugs, I need to change plugs. Presently running NGK-BR6FS at .035 gap. The engines are slightly modified mark 4 454's with approx 375-400 hp.
What plugs should I use? Heard about the a/c mr43TS extended tip. Also what should I set initial timing at?
How would you check for a possible vacume leak at the intake manifold?
thanx

you didnt say what ing you are running if running the stock ign use the br6fs

Forgot... yes running the stock merc. thunderbolt ign. Due to carb set up fowled the others pretty bad. Did not know if there was a better choice of plugs being it's such a pain to change them.
thanks.

NGK's seem to foul least of most brands and they idle best too. I always used them.

Most folks I know that tried those Splitfires had problems with "missing" for some reason.

Nippendenso "hot u" plugs do very well.

ngk,best plug made

Thanks to all, NGK's br6fs it is. Thought so but just wondering. Now if I can just figure out how to get to those in between the engines......................