I also forgot to say that my car is 10.6 comp and I run 92 pump. Ron

What’s the timing light being used?

FWIW, I’ve never dynoed anything where the best power was made at 28* timing.

High VE means higher cylinder pressure: less spark

Come on now, you know you meant less lead, not less energy on the spark plug tip? correct

Here are some pictures of my timing light. It is still set at 28 degrees from the last run.
MJ

Here are some more pictures of the #1 and #2 spark plugs. The first 2 are #1 and the last 2 are #2. The one turned out real well and should help analyze.
MJ

What plug n heat range...........looks rich, wet and unhappy........

Your plugs look horrible. Either those plugs have 100,000 miles on them or else you have something really wrong with your tune. Here is a plug out of my 514 engine after making 900 hp on the dyno. This engine is 15:1 compression.

Dial-back timing lights...... I don’t trust them.

The first thing I’d do is get a light without the dial-back feature and redo the test at the track.

That is another possibility. Your timing light could be lying to you and you are actually running 40 degrees of advance. That is why your plugs look like that and would explain why the engine is happier when you retard it a few degrees.

Those plugs look quite unhappy....First how many passes are on them? What plug is it?

I thought I was the only one that felt this way. Only used two dial-backs, and they were both incorrect. I'm still using my 45 year old Sears non dialback timing light.

Have you ever dialed zero on that light and checked the timing? I'm like the other guys, have doubts about the accuracy of the timing light. Only reasonable explanation or best power at 28 degrees.

Those plugs in the pics have short straps, mine are NGK BCP7ES have straps that are over the electrode. Any benefit from a short strap ?

The short strap plugs are a little more fool proof. I like to use them on high compression engines. I don't think there is a power difference, they are just a little more robust since it is harder to bend the strap if someone on your pit crew drops the plug on the ground when you aren't looking.

The exposed gap into the combustion chamber is usually a small benefit for race motors, especially if your close to the piston tops with the plugs
Try them and see if you like them

The plugs have no more than 20 passes on them.
I have attached a picture of a new box of plugs.
They are Champion product number 297 plug number C61CX.
The heat range is the 61 in the part number.
I hope this helps?
MJ

Lawn mower plugs...........

Nothing wrong with that plug. I use champions and that's all I use unless the customer has some weird aversion to them.

That 61 is a fairly cold plug, yet those look hot. Unless you are at sea level and 15:1 that plug should be the correct range. You can try the 59 but I'm not sure what's going on.


You got a ton of fuel moving through the engine, no timing and plug that looks hot. Something is weird.

I just skimmed back through the thread and you are at 12:1 so that plug SHOULD be too cold. I would have started with a 284/C65YC or if you don't want the extended tip you can use the 285/C65C and tune from there.

So I've switched horses mid stream. I'm going to say get a hotter plug, verify TDC and your timing light and tune from there.

As AndyF said your plugs look bad. Sometimes looking at pictures isn't the same as looking in real life.

If there is no reason you can't run an extended tip plug, I'd use the extended tip.