What are the right spark plugs

[Roger D.]

What are the right plugs for my 1969 restore. Car had bosch plugs. Car is 350/300 hp bored 30 over with a mild cam. To be original i guess some sort of ac plug, maybe 44s. Not sure, need some help.thank you and where to get them
Roger

[Edward J.]

Re: What are the right spark plugs

Roger, I would say 44's would be fine, or even a 43 would work.

[Wayne M.]

Re: What are the right spark plugs

According to GM 1969 Engine tune-Up spec's, AC-R44 (std), or AC-R43 (cold).

[Duke W.]

Re: What are the right spark plugs

Spark plug heat range has been discussed a zillion times including this thread in the past week:

https://www.forums.ncrs.org/showthre...-Running-rough!!!

In particular, look at post #13.

Duke

[Joe L.]

Re: What are the right spark plugs

According to GM 1969 Engine tune-Up spec's, AC-R44 (std), or AC-R43 (cold).

Wayne------


Yup. All 1969 and later Corvettes originally used resistor-type spark plugs.

[Roger D.]

Re: What are the right spark plugs

Wayne------Yup. All 1969 and later Corvettes originally used resistor-type spark plugs.

Okay , I got it thank you everyone. I assume that most of the vendors have them like ZIP, Paragon, etc.

[Joe L.]

Re: What are the right spark plugs

Okay , I got it thank you everyone. I assume that most of the vendors have them like ZIP, Paragon, etc.

Roger------


It depends what you want. If you want plugs configured exactly as original, then you'll need to find some really old NOS plugs on eBay. They're not hard to find although they may be a little pricey.

AC R43 and R45 plugs are still available from AC Delco or GM dealers

[Duke W.]

Re: What are the right spark plugs

You can buy a set of proper heat range AC plugs at just about any auto parts store, and they can cross reference the AC plug you specify to any other brand, or you can do it on the Web. All spark plug manufacturers have catalogs and cross reference charts on the Web.

Duke