Spark plug for EFI

[RemCharger]

A popular song from 1969.

15 yrs B4 Micheal Jackson

 

[gkent]

Tell me more = I have a 383 motor and it runs bad. I has solid lifters so I check the valve adjustment and set at 28 intake 32 exhaust. I then took the spark plugs out and they were black and one looked like it was dropped because the gap was very small. The plugs I put in were RN 12 YC and have a long reach. They are iron heads - I'm wondering if I using the wrong plug and maybe the piston is hitting the end of the plug - actually had two plug that looked like they were dropped with no/or small gap. It's a new rebuild and am trying to get it to run good. Has a mallory HFire box and a mallory coil - should be getting good spark. Efi mallory distributor. Suggestions/help appreciated...

You should be using a RJ12YC

The "J" is the proper length plug. Start there at least.