Spark plugs for 396 / 325 hp

[marriest]

What kind of plugs should be in a 1969 Camaro BB Pace Car RS/SS 396/325 Hp. It has AC Delco R43 xls in it but the Owners manual says R43 N.
What is recommended?
Terry

[bertfam]

Terry, I moved your thread to Maintenance, but if you have a "show car", then you'll need to spend the big bucks on the ORIGINIAL "GREEN RING" R43N PLUGS. If not, then I like Autolite and AC Delco. I stay away from Champion since they just don't last.

Ed

[marriest]

What is the difference btw  R 43N & R 43 xls

[bertfam]

I don't believe there's any difference performance wise. The XLS is just the latest version that's being sold. More info on Delco numbering system HERE.

Ed

[Mike S]

The XLS allows the gap to reach a little further into the chamber. I run those mainly.

Mike

[adjudimo]

The XLS is what I use to run in a 396/325. And I agree with Ed. Stay away from the Champion's.

[1stgen68]

I run R44XL's in my 396 gapped at .40

[ko-lek-tor]

Little off topic. I have heard the best plug is NGK. I can't seem to find a number to cross over though?

[169INDY]

396/325 68
NGK Stock No. 2635
G R 4

[ko-lek-tor]

396/325 68
NGK Stock No. 2635
G R 4

Thanks!

[Charley PHX]

Couldn't find the chart linked in #3 above (2020 post)... So I went looking for the document & found it (I think?)...

Updated link (AC/Delco numbering system):  https://assets.sparkplugs.com/lc/ac%20numbering%20system.jpg 

The host site appears to be kind-of a "Spark Plug University" of sorts... Connoisseurs can just go plumb crazy at:  https://www.sparkplugs.com/

Here's another link to multi-manufacturer data:   https://www.sparkplugs.com/learning-center/5-charts-tools

I'll open a new thread with this reference info. under a more general subject heading. ( http://www.camaros.org/forum/index.php?topic=20356.0 )
Moderators, pls. edit subject title and/or move as deemed appropriate?

ENJOY...

[HOGDADDY]

I have been running Champion plugs (RC-12YC) in my Edelbrock RPM heads per their recommendation for years and never had any problems.
They are 1/4 " shorter for header clearance also.

I just replaced a set and probably wasted my money. The plugs looked ok. They were pretty old.