69 z sparkplugs

[x33rs]

I run Autolites in mine. I see better results with the heat range changes. I tune mine with a wideband to dial the carb in nearly perfect. Living up here at 5,000 ft I routinely drive the car down to sea level so I tend to tune where I find a happy spot for both.

I found the Autolite 86's work best. Equivalent to ACR45S (extended tips). They stay clean up here at 5,000 ft running just slightly rich 12.5-12.8-ish AFR's, and low to mid 13 AFR's at sea level. I stagger jet the carb for best results. Wife drives it daily up here and routinely gets 14.2-14.5 mpg with it in stop and go traffic.