I've been fighting with a ping issue at wide open throttle. Especially up hill. I've recieved distributor. Welded and filed governer .380. Initial timing 12 degrees.
It's a 225 with 7.8:1. I've had this issue with several different carbs installed.
Someone recommend going a step colder in plug. I took my 13/16 plug socket to shop and won't make it down there for maybe a couple days. But I'm 80-90% sure plugs are autolite 66. Should I look into getting 65s. Or would I benefit from the ngk ZFR5N.

Also on an unrelated issue I've been fighting a rough idle too. Same deal, no difference with different carbs.

I like how the autolight plugs work. I think mine are the 25. My book says to gap them at .035 but after putting in the MSD box Ive made it .040.
However Im not so sure if it would be a plug issue since you keep having a rough idle. I would look for a vacuum leak. You might be getting to much air at WOT. If you do pull your plugs look them over well to see if a cylinder is running to lean.

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~Nic

No intake leaks that I can find. I've tried everything but change plugs. Original plugs since rebuild about 12-13k miles

wow. Ive never seen plugs last that long. Even the new iridium ones. The old copper tops conduct better than iridium but have a much shorter life. Even if you regularly regap them.
How are your rubber hoses? I change my vacuum advance and PCV hose every 4th to 5th oil change. This may be over kill but there close to the motor and the heat drys them out. I would also check around the base of the carb. When I had the original 1bbl on the nuts tended to back off until I put lock washers under them.

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~Nic

The "winter blend" of gas this year has been especially bad. I had to change over to premium and detune the engine to survive this winter. Spring is around the corner and the gas should get better.

The extended tip plugs help smooth out the idle............


But I'm thinking you're leaning out.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

NGK plugs are much higher quality than Autolites (which are now Chinese trash). I don't know that the extended-nose NGK ZFR5N plugs will calm down your ping issue, but they might help a bit. How likely is it that you have a good old-fashioned case of combustion chamber carbon?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Only 12-13k miles on motor. Last time I looked at plugs they were tan in color with no sign of carbon. Hard to say for actual chamber but likely fairly clean. I think Ill order up those ngks and try em out tomorrow. I can get em within a few hours of ordering.

What is your total timing? What happens if you go to 10 initial?

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

I forgot what total timing was. But the governer is .380 which I guess is a tried and trued length. Still pings at 10.

Your going to need to hook your timing light back up and check your total I think. That is the easiest fix if it is too much.

Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

It could be your timming lght ortimming marks out also

So I changed plugs yesterday to the ngks. Old plugs ended up being champions rn14yc. A couple had a little red/pink colored spots. A nother had some yellow. Sorta weird. Plugs has 13,071 miles on them. Plugs in general looked a little lean maybe, more tan than brown, but not bad.

From ngk website. The zfr5n are 1 step colder then the rn14yc. As far as my pinging goes, it's better. It still pings wide open throttle up a steep hill, but not as bad, and also can tell it has a little more umph, when getting on it.

With vacuum hooked up, I have 50 degrees advance. And 30 degrees without vacuum. This is at 12 degrees initial

That's way to much with vacume. I usualy ignore the readings just put the timming just late enough so it won't ping pinging will eventually do damage. If you wnat to go by specs usualy since all slants are similar compression and cam if stock time the engine using the spec for the year of the distributor not the engine some of specs were 2 atdc or 0 initial timing without vacuum hooked up. And or someone could have the wrong vacuum advance pot on the distributor giving a odd combo like that.