My engine runs on propane, and I don't need hot plugs at all. I ran a set of very cold NGK racing plugs for a while, but the ignition noise caused havoc with my engine control system. They were, otherwise, excellent running.

It's a late model head, with no drool tubes, and the plugs are the smaller, taper seat plugs.

I've not been able to find much of anything besides a heat range cooler Champions, and couple ranges cooler NGK's. My plug choice is generally Champion and NGK. I am running EDIS igntion and a six cylinder Chrysler coil, so the plugs get 2x the normal number of sparks. I don't expect super long plug life. I've used Bosch platinums in another slant six, and they were truly horrible. So were the Autolites. They'd look almost unused, but still stop firing when cold or under load.

What I'd really like is something at the coldest range possible, that's still resistor plugs.

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'81 W150 on Propane... Oversize valves, Oregon Camshaft cam, 10:5 static CR, Distributorless ignition, megajolt timing controller, PowerTrax lockers.

Nobody?

Man... there's gotta be something out there...

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'81 W150 on Propane... Oversize valves, Oregon Camshaft cam, 10:5 static CR, Distributorless ignition, megajolt timing controller, PowerTrax lockers.

You've gone to the UR6?

Your ignition is waste spark? Positive/negative plug? There really isn't much out there for a peanut head.

UR6IX perhaps.

CJ

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Part of Tyrde-Browne Racing

Since all the vehicles that this plug was used in were in the emissions era, "cold" didn't exactly cross the design engineers mind.

-D.Idiot