What spark plug are you using in your stroked Hemi

What spark plug are you using in your stroked HemI street car pump gas
thanks

I would start with either Champion RC9YC or Autolite #3911 or 3910 is(colder than 3911) or Autolite 3923 or 3924
Any of them will work with iron heads and up to 11.5 to 1 compression ratio on 91 octane pump swill

NGK 4554 (R5671A-8) in my 11:1 pump gas (93) 572" Hemi. I use these when I run it NA and on the street. I throw a colder set in it for nitrous use.

It's a 604 aluminum head 10.2 compression it this make a difference

I have written on paper work I think this what it says real bad writing
NGK NY9
NGK N 11 (i think)

Champion RN11Y

Then say start with 9

This was written in the notes, very messy hard to read

Champion numbers tell you about the plugs, if you wanted to start with RN9YC,R= resistor plug, N=13/16 socket size with 3/4 inch thread length, 9= the heat range , bigger #s are hotter, smaller are colder in Champion plugs Y= extended spark plug ground strap, C=copper core.
On your deal I would start with a cold plug like the RN9YC or the smaller 5/8 socket size RC9YC plugs
IHTHs

I agree with cab. No need to mess with the N series Champion plug. Just use the C series and that way you get the 5/8 hex instead of the big, clunky 13/16 hex.

If you think you need the 11 heat range Champion, I don't think they have that in the C series. Don't have my catalog handy but if that's what you need, you can use the RC12YC instead.

At 10.2:1 compression and pump gas my guess is you'll need the 12 but I'd start with the 9 and work with it. Easier to tune up to a warmer plug than it is to start on the warm side and have issues. IOW, I start colder and then use a warmer plug if I need it.

And this is why I ask. thanks

Looks like Champion is the choice.
I will start with the RC9YC plugs

What do you recommend for a gap.

What ignition and coil are you using?
If a MSD race 7 box with the proper coil set them at .045, if a MSD 6 with a regular coil try .035

RC12YC in mine, gasket left on, 10:1 iron heads. Sheepishly admit that I've never gapped them.