Spark plug recommendation?

[77SSII]

Does anyone have an opinion on spark plugs?
I have a dui w/live wires, not sure of the t-stat temp (if that matters).
Performance distributor said they have had good luck w/autolite platinums and a 0.055" gap.
The truck is a summer only daily driver and has some performance upgrades (cam, compression, 0.060" over & stans tri-ys)
thanks!

 

[Michael Mayben]

The distributor has nothing to do with selecting the proper sparkplug heat range. There would be no need to deviate from the oem heat range of an autolite 85 or 303 or an equivalent plug in any other brand. Use that heat range in order to dial in the carb mixture/jetting, do not swap around heat range or you will be forever changing plugs and chasing your tail.

Also, no conventional spark plug should be gapped greater than 0.045". Doing so will compromise the integrity of the weld of the ground electrode to the plug body and May allow the ground electrode to break off.

I see absolutely no reason or benefit to exceed 0.045" gap no matter what ignition system is being run. I run that gap on autolite 85 using a capacitive discharge ignition box and matching coil that has a potential output of around 50kv. I normally change plugs only when the electrodes are so eroded they look like a melting icicle, any extreme output ignition system will fire a plug with no ground electrode even present (such as a surface gap plug). If the plug will lite off the mixture, then it stays in the hole until it won't...that could be 25>35k miles.