What kind of spark plugs for new 408 Stroker?

[67mopr]

I was wondering what kind of plugs and gap everybody is rinning in their strokers? Is it Champions with the stock gap? Thanks I tried to post pics but it said they were to big.

 

[pettybludart]

What type of heads?Pistons?

 

[67mopr]

What type of heads?Pistons?

Indy X heads J&E SRP Sportsman Class racing pistons, Dish. I think I will go with Champion or Autolite.

 

[pettybludart]

I,ve had good luck with the Auto-lite race plugs.I have the #,s here somewhere,don,t want to give you the wrong #,s.LOL.Auto-Lite AR-3934 gapped at .045.Give them a try!

 

[Darter6]

Stock 68 340's with 10 1/2 to 1 pistons ran N9Y Champions. I think they go by #405 now.

 

[67mopr]

Stock 68 340's with 10 1/2 to 1 pistons ran N9Y Champions. I think they go by #405 now.

oh ok I have a pack of Un opend plugs from early 70's lol

 

[cavemanmoron]

Have you asked the Head manufacturer?
Sometimes they want "shorty" plugs to be used.

I put Autolite plugs in my 318, same number as N-13Y would have been.

If the compression is high, then go with a colder plug, like Darter6 mentioned,
the 340 used N-9y's.

 

[67mopr]

The engine builder said he would take care of it.

 

[chewy]

NGK's go by compression rating. Napa has best price I've found. The other stores will usually match it. I'm currently running GR5's in my 10.5:1 compression engine.

Gapped at .035 because running Dual-Point. When I had HEI in it, they ran better at .045

 

[cavemanmoron]

The engine builder said he would take care of it.

Ask him what plugs they are, so you can get a spare set.

I was the engine builder for my Valiant, I better tell the next owner what I used, my choice's were easier, because I used Factory part number heads.
{casting number #302 heads from a 1988 car}