Correct spark plugs.

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

How much compression are you running?

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

I would run an AR133

ngk 5674-8

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...

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 ?

NGK 5671-8 is what I'd use

Quote:

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Originally Posted by Rodz

NGK 5671-8 is what I'd use

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

I missed the iron head part. lol

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.

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~