[davidgto]

what sparkplug would be recommended for a 65 Original 360 hp 389 tripwr 4 speed and the gap size.

[steve25]

These days you should be asking what brand plug is best and then go to that on line catalog.

The plug gap however would be .035”

[b-man]

NGK would be my brand choice.

[SD455DJ]

Originally Posted by davidgto

what sparkplug would be recommended for a 65 Original 360 hp 389 tripwr 4 speed and the gap size.

Original spark plugs were AC Delco R45S gapped at .035". You can still get them, but not sure if they are American made any longer.

Dennis

[Gach]

Yeah AC Delco R45S, you can have them Cross over to NGk, or Autolite’s I ran Autolite’s but have found NGK to be a better plugs. Get ready to take out loan, there not cheap anymore.

[blueghoast]

Originally Posted by Gach

Yeah AC Delco R45S, you can have them Cross over to NGk, or Autolite’s I ran Autolite’s but have found NGK to be a better plugs. Get ready to take out loan, there not cheap anymore.

Did you use the racing autolite's when you used them.
Thats what I'm using now in my iron head motor

GT

[Formulabruce]

AC 45's are TOO hot without Lead in the fuel.
One can say "but they had these in the 70's Without Unleaded fuel" They also had EGR which technically "cools"the combustion..
AC R44 would be highest I would run. I changed out a LOT of the 45's at my dealership due to changes in fuel.
Alcohol in todays fuel makes your car work harder than it did when new, so why heat it more>?

[Gach]

Originally Posted by blueghoast

Did you use the racing autolite's when you used them.
Thats what I'm using now in my iron head motor

GT

Yes I did, I had to change idle air bleeds on my Pro System, Autolite Race 3933 is plug I always ran. Think it has more to do with heat range then anything. Now running NGK 9

[Gach]

Not meaning high jack his thread, just check my mote says 3924, Put 3933 in that was probably my problem. Blue What number autolite you running.

[unruhjonny]

sorry for the tangent, but I thought that “R4-S” plugs would have not yet been spec’d in 1966;
I am unsure if the OE would have been an “R4-“ or a “4-S”.

I believe that the Delco 45 heat range would have been for the slightly lower compression/smaller cam 4bbl motors, and that the tri powers would have been a Delco 44 heat range;
I think after Delco discontinued the 44 heat range, many people just shifted to a 45.

I tried several different plugs, but was honestly impressed with the autolite plugs;
they seemed to be a good quality plug, at a better price than the NGK’s, and you can still get the Delco 44 heat range in the autolite.

If anyone cared to chime in when the 44 vs R44 vs 44S vs R44S was OE - I for one would appreciate getting that cleared up.

[chiphead]

Seemed like I looked in my 1969 motors manual and it lists R45S for most of the Pontiacs for 67-69. I could look again if anybody really cared.

[Dragncar]

Plugs are stupid expensive these days. I am glad I kept a bunch of new and slightly used Delco 44s-45s, Autolight 86s and Accel plugs. But those JCY18 Chumpions will never see one of my engines again after 2 came apart.
Iron heads I liked the Accel plugs the best.
I will run the HOs again someday.

[chiphead]

So what brand and PN would you guys suggest for a 69 400 with stock compression and a 2802 cam? I've always run R45S, never really experimented with plugs. When I was playing with N20, I ran Autolite 303s, a very cold plug. They would get dark when driven on the street N/A.

NGK's lookup table recommended XR5s for a '67 GTO. it's a 13/16 gasket seat, projected tip, seems legit? Cross reference charts show it to be equivalent to R44S or Autolite 85, so one heat range cooler than R45S, right?

[unruhjonny]

i think when selecting a plug, the compression and cam are key;
Pontiac tended to use two different compression heads in a given year (67-70), and the head more or less determined if a 44 or 45 were spec’d.

[mgarblik]

Originally Posted by Dragncar

Plugs are stupid expensive these days. I am glad I kept a bunch of new and slightly used Delco 44s-45s, Autolight 86s and Accel plugs. But those JCY18 Chumpions will never see one of my engines again after 2 came apart.
Iron heads I liked the Accel plugs the best.
I will run the HOs again someday.

That is interesting. Not really familiar with the Champion plug number you mentioned but I am almost sure Accel spark plugs were made by Champion in Toledo , OH. They were the "Yellow Jacket" plugs they used to market. Personally, I have had about equal results with Autolite, Champion and NGK plugs. I like the way the NGK plugs are packaged with the little cardboard tube over the business end. I have found some Champion plugs with the center electrode crooked in relation to the shell and ground electrode. But they all functioned fine. If I had to pick a "brand" price no object, I do like NGK. Very few defects.

["QUICK-SILVER"]

Originally Posted by chiphead

So what brand and PN would you guys suggest for a 69 400 with stock compression and a 2802 cam? I've always run R45S, never really experimented with plugs. When I was playing with N20, I ran Autolite 303s, a very cold plug. They would get dark when driven on the street N/A.

NGK's lookup table recommended XR5s for a '67 GTO. it's a 13/16 gasket seat, projected tip, seems legit? Cross reference charts show it to be equivalent to R44S or Autolite 85, so one heat range cooler than R45S, right?

Sun tune-up charts, for 69, show the same R44S for engines from 330hp to 370hp for standard/normal(?) driving. Then show R43S for trailer towing and severe service.

So one has to think about what standard/normal driving was in 69 compared to now in order to determine the best heat range for a plug.

Putt-putt around could use an R45S for the plugs heat range/self-cleaning to work.

Where thrashing the hell out of an engine would need something like a R42S.

Clay

[Holeshot71]

I’m a big fan of the NGK plugs. For the 69 high compression heads with the gasket sealing ring type plugs I use NGK XR4 5858. These may also be correct for the 65 389? I usually gap these at .040” with an HEI distributor. With points probably .035”.

[unruhjonny]

Originally Posted by "QUICK-SILVER"

Sun tune-up charts, for 69, show the same R44S for engines from 330hp to 370hp for standard/normal(?) driving. Then show R43S for trailer towing and severe service.

So one has to think about what standard/normal driving was in 69 compared to now in order to determine the best heat range for a plug.

Putt-putt around could use an R45S for the plugs heat range/self-cleaning to work.

Where thrashing the hell out of an engine would need something like a R42S.

Clay

I believe that (speaking purely about 1969 model year 400's) the engines with #48 heads would have have real world compression at or just below 10:1 where as the engines with #62 heads would have have about 9.5-9.0:1 compression.

in essence;

#48 heads = R44S
#62 heads = R45S

The recommendation of going down a heat range for "towing" or driving hard would have meant:

#48 = R43S
#62 = R44S

Now regarding interchange, I personally have never run a champion plug because of all the poor qc issues I have heard or read of - I am sure that at some point before I existed they were a good plug, but that was before my time.

I happened to get a 2002 issue of the autolite spark plug catalog, and used it to do cross referencing for standard plugs (also using google), this is what I get:
(AL = Autolite / CH = Champion / NG = NGK)
R45S = (AL) 85 = (CH) RJ12YC* = (NG) 3332 / XR5
R44S = (AL) 86 = (CH) RJ14YC** = (NG) 5858 / XR4

*From what I am reading, it looks like the champion 11 through 13 heat ranges cross to a Delco 45.
**From what I am reading, it looks like the champion 14 through 20 heat ranges cross to a Delco 44.

[MIke L]

NGK's lookup table recommended XR5s for a '67 GTO. it's a 13/16 gasket seat, projected tip, seems legit? Cross reference charts show it to be equivalent to R44S or Autolite 85, so one heat range cooler than R45S, right?[/QUOTE]


Right
AC plugs get hotter as the numbers increase

NGK plugs get colder as the numbers increase.

The standard AC plug is a R45S gapped at .035 for a ‘65 389.

The NGK equivalent of a AC R45S is XR4which I use and will continue too in my 389
I’ve used the Autolite and Champion over the years and found both to be inferior in my combo.





Mike

[blueghoast]

Originally Posted by Gach

Not meaning high jack his thread, just check my mote says 3924, Put 3933 in that was probably my problem. Blue What number autolite you running.

I still have the box I'll check and let you know. This motor is iron headed too.

GT