What Spark Plug

[Clois Harlan]

What spark plug type and gap is everyone running with their 428?

[Jerry Cowing]

Clois.

I use a number of plugs and there doesn't seem to be a difference in my 428 FE. These are my Street/Strip plugs, I use cooler plugs for competition:
Motorcraft BF-32 or BSF-42C (resister)
Autolite 35 & 34 or 45 & 44 (resister)
Champion F-11YC & F-9YC or RF-11YC & RF-9YC (resister)
Accel 378 & 375 or 675 (resister)

I use an MSD electronic ignition therefore I use 44 (street/strip) & 40 (competition) spark plug gap. If you use a point system, you'll need to use 35 & 32 gap, respectively.

Hope this is of some use to you.

[Dave Samson]

Jerry,

Why open the gap so far in conjunction with the MSD ignition ?

Have you tried the smaller gap with the MSD too ?

[Back in Black]

Having seen the MSD active displays, with plug simulator/visible spark, I can attest that the gap can be extended to over an inch, and still look like one bad to the bones plasma discharge.
I am therefore convinced that the MSD has some major gap jumping properties...the gap can be way wider than with a standard ignition, and that means more fire in the hole. It also revs way up high and does not fail to make the 1 inch (or more) jump at those high revs, (like 10,000 rpm plus)

So my car will have the MSD works.

[Dave Samson]

Great, now someone will invent 1" gapped plugs, what next ?

[Clois Harlan]

Ok I have used three sets of plugs lately, Champion RC12YC, Autolite 985, Motorcraft ??. Both Champion and Motorcraft are the same plug based on the RC12YC, gapped at .034 ".

Yesterday I bought the Autolite 985 plugs (crossover for the Champion RC12LYC) and if I use them I will gap them at .048". I too am using the MSD 6AL box. I actually bought these by mistake and was going to take them back and exchange for the shorter gap plugs but I think I may try them with the wider gap.

The Champion RC12YC are the recommended plugs for the Edelbrock aluminium heads. Any reason I shouldn't try this other than the $1.09 per plug cost.

Clois