69 z sparkplugs
 

Does anyone know the correct ac spark number for a 69z? thanks

AC Delco Acniter R44 is the go to plug for Z/28 as far as I know. Many people run the hotter R45 and some have tried the colder R43 plug but they're usually not well suited to the street and tend to foul.

I got a set of R43 off eBay a couple years ago and last year got a couple sets of R44 from another member here on the forums.

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If by "correct" you mean what it came with from the factory, that would be R43.

Most guys run R44. They don't seem to foul as easily. Some guys claim the R43 helps keep detonation down.

Checked my notes and the assembly-line correct R43 plugs should have 4 equal green bands and the word 'ACNITER' on the porcelain.

I have a box of R43N and the outer carton says "New" Acniter. Anyone know the difference between the R43 and the R43N?

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R43 is a 3/8 reach plug (3/8 inch of thread).

R43N is a 3/4 inch reach plug.

In and out of the trailer or car show I would go to 44's or 45's John. 44's if you are going to drive it around. Take those cars out to the Curly Top or to get a newspaper on Saturday mornings Johnny. Its good exercise for them!

Honestly, I like my Holley's. They burn good winter-summer with no real issues.

----Big believer in Autolites in a driver!......Bill S

I had to use 45's with my x-ram. I am with Bill on the autolites, they do not foul as quick.

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.