Spark Plug Recommendation

[Road Grabber]

I have a 1970 383 with closed chamber heads and was wondering if anyone had spark plug suggestions.

Standard Holley 4 bbl and magnum cam.

Closed chamber iron heads should bring it up a half point?

Thank you

 

[QOTHL]

Just my 2¢ I use NGK.

 

[Aron Gleason]

Ngk xr5

 

[WileE]

Champion J-11Y

 

[Mebsuta]

Champion J12YC.

I don't have a radio or anything, so I use non-resistor.

 

[Geoff 2]

Same heat range as the factory recommended but NGK, 5 heat range.

 

[66Satellite47]

My opinion is the Champion J11YC is a good heat range, but I'd use the NGK that crosses, or an Autolite.

 

[Road Grabber]

Thank you for the replies.

Has anyone tried the Accel?

 

[QOTHL]

Champion J-11Y

What the heck do Klingons know about spark plugs!

 

[WileE]

Thank you for the replies.

Has anyone tried the Accel?

Accel shorties come in handy for header clearance.

 

[moparedtn]

I have a 1970 383 with closed chamber heads and was wondering if anyone had spark plug suggestions.

Standard Holley 4 bbl and magnum cam.

Closed chamber iron heads should bring it up a half point?

Thank you

What are these "closed chamber heads" of which you speak?

 

[WileE]

What are these "closed chamber heads" of which you speak?

Referring to the "915" 67 heads.

 

[moparedtn]

Referring to the "915" 67 heads.

Wow, I didn't even see the OP's lips move!

 

[wagonman]

Accel shorties come in handy for header clearance.

Good luck finding any unless NOS. I ordered some from Summit for a Blue Print 383 Chevy 3/4 14mm gasketed plug, they were advertised as a shorty but only 1/8 inch shorter. Sent them back. Think NGK or Nippon Denso makes them, not made here anymore.