Took my car to the chassis dyno yesterday, only got 3 pulls in before the computer on the dyno stopped working.
520 RB with ported TF 240 heads, 10.1 CR, running a 1050ish Thumper Carb 90 octane non ethanol fuel. NGK-6 plugs

Started the engine with fresh plugs, warmed it up and did the first 3 pulls, pulled the plugs, they were white on the strap and very little color on the base ring, the color change looked to be on the base of the ground strap near the threads.
We jumped up 3 sizes on the secondary jet,knocked total timing from 38 back to 33.

We did the second set off 3 pulls, and all the data went away, operator had to reset everything and start over. At that point we had to call it quits, he needs to order something, but anyhow..

.Are the distinct marks on the ground straps the timing mark, or is the color change at the base?
The marks towards the electrode end of ground straps are very pronounced, I was careful pulling them, don't think it was from touching anything.

Any help is appreciated.

Hot & lean..............

To me looks like too much timing, too hot of a plug and not enough octane.

looks like timing too far down strap,should be as its going down strap

Use 34 or 35 degrees of total timing with the Trick Flow heads. AFR at full throttle should be 12.8. Did you have a wide band hooked up for the dyno pulls? If you don't have a wide band you should install one. Cheap insurance for an expensive engine. NGK 6 should work just fine in that engine. That is what I run in all of my pump gas stuff.

Andy he said it was on a dyno but the computer went out and he lost all his data.

Which pictures are for the second set?
I've never had a BB Mopar, pump gas or race gas, that liked more than 36 degrees total timing anywhere
Iron heads and aluminum heads from 8.5 to 1 compression up to 15.3 to one on E85 seem to do well with 34 to 36 degrees total timing
As far as jetting it is much better to get equal fuel ratio to each cylinder instead of fattening up the secondary only More power and heat made from all cylinders, not some hotter than others

Thanks for the response guys, sorry so slow, work has been hectic,

I was wondering if those sharp marks were timing marks, they almost look like marker marks they are so pronounced,.

I do have an AFR, but only with the exhaust installed. It shows high 11s WOT with the 3" exhaust on. Dyno guy had a probe that clamps on the side of the collector, not really an accurate setup with short collectors. Next trip will have collector extensions with my O2 sensor in it. FWIW, the first 3 pulls showed a pretty flat AFR line, but showing high 13s set up that way. Idling you could see lean spikes from reversion.

Those plugs are 2 from each side, front and rear of each side, after both sets of 3 pulls.

The engine temp on the first pulls was 210, where my normal temps are about 185-190.
Maybe that would make the pugs seem whiter than normal?

OK Cab, you brought up something no one else has, making the secondaries richer than primaries, and affecting cylinder distribution.
So I have had a [censored] of a time getting this carb dialed in for my car.

The carb is a cast body 4500.

The problem I had setting this carb up is a flat lean spot off idle. My car is a 4 speed, so when the clutch is let out, and the throttle is applied, you can watch and see the AFR jump up about 3 points after the pump shot get used up

. Dom is very helpful, had me change IFR, IABs, and even sent out some larger transfer slot jets.I really don't know squat about carbs past setting idle up and main jets.
All these changes made the cruise go rich after the transfer slots were reached by the throttle blades.

The issue seems to be,when the carb is squared up, the transfer slots are too high in the bore to be effective where they are.
.By closing the secondary blades, and opening up the primary blades, the transfer slot just on the leading edge of the blades, my lean spot is gone. I had the secondaries disconnected, and got the primary side AFR working great. There is about 4 full turn of difference in the idle screws between front to rear.

At cruise on the primary main jets, it runs mid to high 13s., heavy acceleration is low 12s with only the primaries. I was so happy with how it was running, though I could make up the rest with the secondary jets.

So having a large jet split is bad for distribution...did not think of that. &^%%$$$$#@$#%$%!

Thank you guys for the help.

We are here to help, if you don't test and learn you'll never go faster
I would be tempted to try a set of NGK 7 in the car with the AFR in the mid to high 14.+ AFR. The 6 may be a tad to hot now My old pump gas 518 C.I. low deck stroker really like 14.2 to 15. 3 AFR at light part throttle cruise below 2300 RPM with OR pump swill at 3500 Ft. above sea level with semi dry air
What List # is your Dominator?

Hey Cab,
I was looking at maybe going to an Autolite plug but the conversion charts are all over the place, I will try one step colder though.

I think Dom buys the carb bodies without a list number, at least I didn't notice one.

So at what jet stagger does one start running into distribution problems? Should I do something different?

look closely at all eight spark plugs and jet from there
Don't be afraid to use the idle mixtures screws to fine tune the carb., especially at idle and light part throttle cruise
Single plane intake motor with one carb can be challenging to get them perfect, you may have to settle on a comprise that makes you happy
As far as a Autolite plug try a # 3923