[weranc55]

I need to replace the plugs on my ra3 and they do not make the ac delco r44s anymore. Does anyone know a good substitute for that plug. I dont want to use the r45s. I think its to hot of a plug and gas is not what it was in the past.

Thanks

[unruhjonny]

I have found that the R45S or R43S work just fine.

The R45S was the plug that the 70-L78 was supposed to use (same heads), and the R43S was the plug designated for "high speed driving".

If you are considering not using a Delco plug, I put a fair ammount of research into equivalent plugs;
I will give you two alternate plug brands, but I personally don't like chamions, they always seemed cheap, and I have heard of more than one time where they admitted their heat ranges were way off. I like Autolites or NGK (I don't have comparable NGK numbers handy - PM me if you want them)

R43S = Autolite #84* = Chapion RJ-11-YC
R44S = Autolite #85 = Chapion RJ-12-YC
R45S = Autolite #86 = Chapion RJ-13-YC*
(* = I'm not sure these plugs exist)

I hope this helps!

[GRNMTGOAT]

Just went out and looked at my newly rebuilt stock RA3 motor, Paul S has used Autolite 85's, they must be OK ! Bruce.

[weranc55]

85's it is. Thanks for the help.

[giles]

Originally Posted by unruhjonny

I have found that the R45S or R43S work just fine.

The R45S was the plug that the 70-L78 was supposed to use (same heads), and the R43S was the plug designated for "high speed driving".

If you can find a set of R43S they should work just fine. I have run them in a stock RA3 without issue. The area where "cold" plugs will cause issue is during winter cold starts (below freezing). The colder heat range is much more suceptible to fouling. In warmer temps the cold plugs are better for detonation avoidance, thus the "high speed driving" recommendation.

For almost everyone here, who I assume drives their cars on nice days, and does not slog through winter commutes in sub-freezing temps, one or two heat ranges colder than OE is a good choice.

[briann]

Originally Posted by unruhjonny

I have found that the R45S or R43S work just fine.

The R45S was the plug that the 70-L78 was supposed to use (same heads), and the R43S was the plug designated for "high speed driving".

If you are considering not using a Delco plug, I put a fair ammount of research into equivalent plugs;
I will give you two alternate plug brands, but I personally don't like chamions, they always seemed cheap, and I have heard of more than one time where they admitted their heat ranges were way off. I like Autolites or NGK (I don't have comparable NGK numbers handy - PM me if you want them)

R43S = Autolite #84* = Chapion RJ-11-YC
R44S = Autolite #85 = Chapion RJ-12-YC
R45S = Autolite #86 = Chapion RJ-13-YC*
(* = I'm not sure these plugs exist)

I hope this helps!

Yes the ACDelco R43S plugs do exist. I just bought 8 of them today.

[unruhjonny]

Originally Posted by briann

Yes the ACDelco R43S plugs do exist. I just bought 8 of them today.

I wasn't wondering if any of the delco plugs existed, I think this is common knowledge...

I just don't know if the one champion or autolite coded plugs exist.

[briann]

Originally Posted by unruhjonny

I wasn't wondering if any of the delco plugs existed, I think this is common knowledge...

I just don't know if the one champion or autolite coded plugs exist.

ahhh ok....my bad....

I actually thought I had the coldest plugs in my engine and was quite surprised this morning when I found out otherwise.

[tdavidl]

had my 71 400 rebuilt 5 yrs ago to RA III specs and autolite 85s. pulled a plug today to check gap and it was .026...can anyone confirm that gap for RA III 400 autolite#85?

[Transamric]

Originally Posted by tdavidl

had my 71 400 rebuilt 5 yrs ago to RA III specs and autolite 85s. pulled a plug today to check gap and it was .026...can anyone confirm that gap for RA III 400 autolite#85?

Plug gap depends on what ignition you're using. A hotter ignition like a big cap GM HEI can take advantage of a wider plug gap of .045" to .055". But a basically stock points ignition will need to be narrower at .028" to ,035".

[tdavidl]

thx TA ric...i replaced points with a petronix unit...wanted more reliable, lower maint ignition...so i suppose they matched the gap to this unit...was just curious as i remember back in the day my gap use to be in the mid to high 30s if i recall correctly