Correct spark plugs.

[dw driver]

Looking for advice on what spark plug to run on Dart Platinum steel heads. Will be running the motor on 112 octane gas. Thanks.

[dereksehi]

How much compression are you running?

[dw driver]

Running close to 14-1 compression. Rules change forced us to a steel head. We were running the Dart Pro 1 alum. heads.

[dereksehi]

I would run an AR133

[stockcar5]

ngk 5674-8

[DANNY]

Both plugs are good though the ngk is far less I ran the ar133 and now run the NGK. I had been having issues with the ar fouling also...

[dw driver]

Thanks for the response guys. Would prefer to run the NGK plugs. The correct plug us the NGK 5674-8 for these heads on gas. Right ?

[Rodz]

NGK 5671-8 is what I'd use

[stockcar5]

NGK 5671-8 is what I'd use

i dont think a .750 reach gasket seat plug will work. darts take a .460 reach taper seat.

[Rodz]

I missed the iron head part. lol

[js11]

Most iron heads I've run required the tapered seat, not the gasket seat. The dart web-site should have a tech link or description of that particular head that gives tech details, including the recommended plug for gas, alky, etc. When in doubt, find the manufacturer's specs.

[RACR_73s]

I have NGK r6573-8 in my steel heads, what is the difference between them and the r5674-8? which would be better and why? ~Thanks~