What are these plugs saying to you.

[1969cuda]

These plugs have 10 passes and probably 15 street miles on them.

 

[74 360 dart sport]

The far left 1 on top looks good the 2 middle ones look rich the far left on the bottom looks like metal pieces the rest look a little lean not bad

 

[1969cuda]

The little metal looking pieces might/must be from the aluminum heads?
Thanks for the reply.

 

[Bewy]

Rich &/or too cold. Unless a power adder is being used, should be a 5 or 6 heat range in NGK.

 

[Newbomb Turk]

What fuel? What’s your compression ratio?

 

[Bewy]

Carbon is as good conductor of electricity. The badly carboned plugs could be losing you power by shorting out the spark.

 

[1969cuda]

110 Sunoco with 10.25:1
These NGK’s were R5671A-9.

 

[Newbomb Turk]

110 Sunoco with 10.25:1
These NGK’s were R5671A-9.

That’s a ton of octane for your compression ratio.

That plug is way too cold.

It’s dead rich.

 

[RustyRatRod]

That’s a ton of octane for your compression ratio.

That plug is way too cold.

It’s dead rich.

Yup plus no projection whatsoever. The turtle has his head in the shell.

 

[Newbomb Turk]

Yup plus no projection whatsoever. The turtle has his head in the shell.

He certainly would benefit from a projected tip.

That fuel is probably killing 20 hp. More octane than you need is a power killer.

I have a 395 inch engine out there in my friends car that did 505 hp at 6200ish that is 11.1:1 measured with iron heads that runs on pump premium.

It also did that will 2.02 valves and just some bowl porting and I rolled the short turns a bit.

There’s no way I’d run face fuel through it.

 

[1969cuda]

I’m going to throw in a set of NGK BKR5E and some 91 octane and see what happens.

 

[Dart Frog]

I agree there's no reason with a good tune that it shouldn't run good on pump premium. Especially if it's an aluminum headed motor. Open chambered iron heads may be a little grumpy with that compression ratio I feel you're getting right at the edge. Like said two look good two look a little rich but with that fuel it's hard to say.

 

[crackedback]

That fuel is probably killing 20 hp. More octane than you need is a power killer.

Yep. When racing a long time ago, one specific class, guys were running to the race pumps for fuel, 105-110. I got asked by another racer, what I used, CK Special Blend. Never heard of it.

It was the fuel from a Circle K 87 octane. I outran most of them on the long straights. We dyno tested race fuel vs the pump and the pump was better bottom to top. A couple of real cheater engines had me. The legal stuff nope.

 

[Squishy]

I agree, your plugs are way too cold. I ran heat range 9's in my race motor that was 15:1 CR. I would recommend making your changes one at a time so you can pin down what improves and what doesn't. Too many changes and you won't know what helped. The higher octane fuel is probably not needed, but I would change the plugs first to see if they clean up. Do you know your total timing?

 

[1969cuda]

32*

 

[Squishy]

That's pretty safe timing, my guess is it will like at least a couple more degrees. As you add timing it will lean out if it's rich.

 

[Newbomb Turk]

32*

Without rpm that number is useless.

 

[Jeremiah (jd)]

I'd give it a few degrees of timing and run some 6's or 7's. If you switch fuels from 110 to pump 7's and leave the timing. Aside from that it looks rich.

The plug in the pic is a -8 ngk on 112 leaded and a .073 n20 jet at 32 deg advance, for reference.

 

[furrystump]

The strap mark can be influence by heat range. Too cold and it shows good timing, but it’s just cold. Get an appropriate plug and I’ll bet the mark moves towards the body with no timing change.