What spark plugs

[ike61]

I’m looking at getting a New set of plugs for my 383. It’s a 67 2 barrell motor but now has a 4 barrell, headers, stock electronic ignition, 516 heads with larger exhaust valves and mild porting. Stock dishes pistons, mild cam, and 2 and1/2 exhaust. Recommend me a plug brand and should I change the heat of the plug from the stock 2 barrell since I now have a 4 barrell? Thanks

 

[kiwigtx]

Autolite ATL-86

 

[Don Frelier]

I prefer champion RJ12YC or even better an Accel U-groove ( I think they call them C-cut today) but they are pricey. If you have a hotter coil you can gap them at .040"

 

[rlem1977]

NGK XR4

 

[Houle #382]

I put NGK GR 4's in my 68 340. It will never see another champion plug as long as I own it. Big difference hated to buy Jap plugs but the way they ran in my race sled I had to try them. Won't look back