C2 AC Delco Spark Plugs R43 or R45?

[James W.]

I am changing plugs in my 1964 327/300 hp engine. The standard plug is the AC Delco R44 which every auto parts store I've called says that they don't carry them anymore. Tey have either the colder R43 or the hotter R45 or the high priced AC Delco Rapid Fire plugs. I am leaning toward the R45 since the engine has a few miles on it and I will be taking it on some long distance trips this summer then back to around town cruising.

Will the R45 work okay or should I go with the colder R43 which everyone seems to carry? I would like to keep AC Delco plugs in the engine if possible.

Best Regards,

James West
Omaha, NE.

[John H.]

Re: C2 AC Delco Spark Plugs R43 or R45?

James -

I run the R45S plugs in all my small-blocks and they work fine, have nice tan color, and I can buy them anywhere.

[James W.]

Re: C2 AC Delco Spark Plugs R43 or R45?

John,

Thanks for the info.

James West

[Randy S.]

Re: C2 AC Delco Spark Plugs R43 or R45?

What is the difference between R45 and 45S?

Randy

[Dave S.]

S = Extended Tip *NM*