Best plug for LT-1

[Ed Wright]

Originally Posted by Dan Fahey

Bosche Platinum 4 Prong Plugs...

Another plug I have seen too many problems with. Ditto mis-fires, sorry I meant split fires. E3 are also problem prone. I have found no "trick" spark plug that makes more power than an AC, Champion or Autolite. Motorcraft plugs are good too.

I owned & operated an extremely busy & successful performance tuning shop for over forty years. Probably sold & installed more spark plugs than most here. Autolite & Champion have, in my experience, been more reliable that any others. I have had ACs with open resistors right out of the box. Look like a bad plug wire on the engine analyzer's 'scope. Zero issues with Champion, Motorcraft & Autolite.

You may have a good set of those plugs, but I have seen enough bad ones I would never recommend them.