Spark plugs

[31 bucket]

due to weather conditions I'm kinda checking things out. I have AC 45 plugs in my engine. I have a super charger. Pro comp mag distributor. Taylor wires. Aluminum RPM heads. The gaps are all over the place. What is a good gap or even plug changes to go with?

 

[Spanky]

AC 45s are a rather cool plug, which is appropriate for a blown engine. I like 'em in my SBC with iron Vortec heads. Actual plug gap is really dependent on coil output, but most electronic ignition coils put out 40,000 or more volts. Gap should be .045 if that's the case.

 

[Spanky]

Re: plug gaps . . . a lot of guys recommend narrower gaps (.032 -.035) even with electronic ignition for improved performance, especially on a boosted engine. Just sayin' . . .

 

[Indycars]

I always thought of the 45 as a mid-range plug and was run in most stock SBC. Also he
mentioned the 45 and you said 45S which is the extended tip and is better if the piston
doesn't hit the plug and close the gap. Most likely he is running a flat top or recessed top
piston so he should be fine, but something to be aware of.

 

[Spanky]

he mentioned the 45 and you said 45S which is the extended tip and is better if the piston
doesn't hit the plug and close the gap.

I was simply referring to the plural of plugs with heat range 45 which should probably have been written, "45's." Good point though, and good chart!

 

[Indycars]

I was simply referring to the plural of plugs with heat range 45

Ah yes, I can see that now!