I need a spark plug number. Autolite or NGK. 572 Hemi. 10.8 compression. Two Quick fuel 950's. Old Weiand TR. Mild mid .600 mech roller. Stage V heads. Mostly street driven. Thanks much.

For regular street plugs autolite 3923 or champion rc9yc are pretty close at 10.75:1 with a wedge/aftermarket head application. The hotter 3924 or rc12yc also works but is a little on the hot side. I've tried to remember ngk numbers and have given up, LOL. Someone else can help with those. I'm going to start out in the same ballpark on my 572 with a little less compression. I would probably start with the colder 3923 on yours and see how you like it. hope this helps.

If you want a non resistor extended gap spark plug try either the Autolite 3910 or 3911 or the equivalent heat range # in NGK, If you want a retracted gap, flush, non resistor plug try Autolite # 3932 or 3933

I use NGK 4554 (R5671A-8) in my pump gas 11:1 572" hemi.

Autolite 3910 or 3911 like Cab said - I run the 3911

Thanks guys. Appreciate it!

The AR3911 is projected tip, and I may be wrong, but I think is about the same heat range as a 3932 which is a retracted tip, and a pretty cold plug. Great for the track, but I wonder how long it would go really driving a bunch.

he said street driving....so, I recommended street plugs.

Guess that takes the fun out of it

NGK BCP7ES