Put some octane booster in.

You been running regular?!

no, 93 octane..wonder what the MOST total timing this thing should be able to stand? 9.5:1 440 bored .030 over, stock iron 452 heads, MP 284/484 cam installed 4 degrees advanced at 104. Holley SD intake, hooker 1 7/8 fenderwell headers, 3000 stall convertor. Idles in park at 900 rpm with between 11-12 inches of vacuum and in park at 700 rpm with 8-9 inches of vacuum.

I have a 1970 charger rt that's pretty much all stock . It pings like a mother if i don't pickle the 93 with a little race gas. I could back the timing down but it doesn't run as good.

What total timing do you have? Is the vacuum advance dropping out at WOT?

Nice to see someone in Moparland still playing with their Thermoquads!

I have a pile of them waiting for when I get my 71 Gtx back on the road.
Always liked the design and I’m sure they can be made to work.
As we all know the tuning parts are not readily available these days?

I was so busy waffling I forgot my reply.
In recent years we have given up playing with vac advance and tuned without it!
Give the engine as much advance as she will take to turn over and run (approximately 14 degrees).
Have a 20 degree advance plate in the dizzy and the jobs a gooden...
Then all that’s left to do is advance spring selection.

Maybe I missed it.

What is your cranking cylinder pressure?
What spark plug are you using?

years ago and i'm talking around 1986 or so] i made some programs for jets, both primary and secondary, and metering rods on a Hardinge CNC machine.
i still have the program and tool sheets, but the program itself is on a paper tape.
the parts worked good on the several thermoquads i tinkered with !
if i had been smart [YEAH, right.......] i would have cranked out a bunch of those parts and sold them in kits like the strip kits had.
i am such a DUMAZZ at times........

Cranking pressure is 150 PSI and i just looked at the plug and they are NGK but no number on them, but i just got them for a 1975 chrysler new yorker with 440 as thats what this engine came from.

also, please verify im looking at the timing numbers correctly: Ok, i have the MP timing tape on the balancer. Using a regular old timing light, i have the distributor at 20 degrees BTDC initial timing..it sits and idles its best at 20. ok, watching the timing tape with the timing light as i bring up the RPM's, it should top out at somewhere between 34-36 BTDC on an engine like this, correct? No matter if the vacuum advance is hooked up or not, it should end up between 34-36 at WOT, correct? Then WITH the vacuum advance hooked up, i may see 40 degrees BTDC at a light cruise, but when stomping it to WOT, it should still drop back to 34-36..correct?

Your plugs are too hot. Go two steps cooler. That might eliminate your problem.

Yes, that is the good way to check. To be safe, I would disconnect the vacum to the distributor altogether and just have mechanical being the ONLY advance it sees. Of course, plug up the hose end, otherwise you've got a small leak.

If this takes care of the problem than you know your vacum is not pulling off when at WOT and your distributor continues to see additional advance beyond just the mechanical.

If that is that case, what is your source for the vacum advance?

oh ya, ive disconnected the vacuum advance and its still advancing too far.

just curious as to why you say the plugs are too hot? Not debating you at all, just wondering..learning.. Here is a pic of one i pulled yesterday when i checked the cranking pressure.

Hay guyz .... if you close-up the secondary door ... it WILL richen the mixture up.

Y ES

You can get secondary jets here; https://www.carbsonly.com/
When i talked to him he only had .134, .137 and .143 but you could drill them out to a larger size if needed. The opening of the air door on the secondary's has a huge impact on mixture

Yes, that's what both B1MAXX and I suggested a few days ago...no response though, so I'm not sure if the OP tried or not?

I did try it..I tightened the air door significantly and even tried limiting how far the air door opens. It MAY have helped a small bit but not near enough. The secondarys have been drilled out for a richer mixture by Demonsizzler who used to be on this site as the thermoquad guru. I have found the timing going way too far.It was advancing into the 50's and with the vacuum advance hooked up, into the 60's! Surprised it didnt ping more than it did! How does the colr of that plug in the pic i posted above look to yall? It red in color instead of tan? Its not black and rich looking though..

Have you tried driving (flooring) it without the vacuum advance hooked up? Did it ping? If not, disconnect it, set the total timing to 34* Then take it out for a pounding. Did it ping? If yes you need more octane. Red deposits on the plug are usually from fuel additives/ octane boosters. The plugs look fine to me.

If it does ping you could try a colder plug, as stated previously. I always ran a #85, I see though now the listing at the parts store is an #86 which is hotter. Maybe you got the hottest plug they make for that ap. I know that an autolite #86 is the hottest version of that plug. I can't believe that NGK doesn't have a number on their plugs, that's got to be the dumbest thing a plug company could do.