Can't I order a 1973 (that's the year car the carb is off of) choke thermostat for it?

I'll get the carb number off it so we can see just why year it really is.

I'm trying to keep this car stock looking as possible. Otherwise I'd be all over that electric choke kit!

That choke thermostat is a one-year-only item. You might still find one, but it's not adjustable, which kinda sucks. For the same or less money, you can get the better, fully-adjustable electric choke kit and wind up with a better result.
The number of people who would ever peer under your hood and go "Hey! That's not a stock choke!" rounds down to zero.

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

Just took the last 3 hours to tune this thing to the best I can get it. Followed the in depth rebuild guide posted by Dan and a sheet from a rebuild kit for the figures and measurements. Also re-adjusted the idle speed and mixture as per Dan's instructions. As we know, still running the 1920 carb with the stock 612 jet in it. Here we go:

Choke tuned to 1972 standards. 1/16" gap on the second step of the fast idle cam, 5/32" gap when the choke pull off is applied (measured with a vacuum pump holding 15in of vacuum on the gauge). Tweaked 1945 choke stove rod a bit so it wouldn't be holding the choke closed for so long. High idle set to ~1600rpms.

Carb set to 800rpms in Park for curb idle. Idle screw 1.75 turns out (which I take to be a good thing). Sprayed all fittings, shafts, hoses, etc with carb cleaner with engine running. No leaks found. Holds a steady 19" vacuum reading while in park. Accelerator pump set to middle hole and shoots a very healthy stream of gas each time it is stroked.

Checked timing (again) with vacuum advance disconnected and plugged. 7* Initial timing. Since my distributor puts out 11.5* at 2300 rpm, that would make my total mechanical timing 18.5*. Then if my vacuum advance put out another 10*, that should put me somewhere around 28.5* Total overall timing. Is this correct? I'm still muddling my way through this part...

Pulled all the plugs. All are Dark tan and have some soot on them. Gapped to .035" and reinstalled. Champion stock plugs (RB13NY I think) Cap and rotor look good (better be since they were new 5,000 miles ago).

Catalytic converter is removed and bolted a piece of pipe up in place of it.

Heat riser time! When cold, pull it back and it springs back shut quickly. When warm, pull it back and it slowly shuts itself. Blip the throttle and it opens 3/4 of the way then springs back shut. Get it HOT (as in melt your hand to it kind of hot), and it opens automatically to about halfway open, and opens fully when you blip the throttle. Does this sound normal??

87 Octane gas.

Tranny adjusted so it shifts nicely at about 22mph (2nd gear) and 34mph (3rd gear). Downshifts with my foot halfway to the floor on a hill, and roughly 3/4 of the way to the floor on flat ground.

Freshly washed and waxed so wind doesn't drag as much lol (just kidding there).

Thoughts? Opinions? Free beer?

That's higher than I'd probably go.
If all these figures are crankshaft degrees, then yes, that's right.
If your experience is like mine, you'll be much happier with NGK UR5GP plugs.
Good...
"Slowly" like it moves slowly/binds (bad), or do you mean the spring tension is weaker (fine/normal)?
Yes.
Good.
Good choice.
Sounds about right.
Clean cars run better.
Sounds like you're happier with how it runs now than you were before, so that's good. Unless it's been changed, you've got some very old transmission fluid in there; you may want to change it to a good brand of the newest Dexron-VI fluid, a quality filter, and the nice Chrysler leakproof pan gasket. Likewise, fresh rear axle lube is a nice idea, and there are lubrication points all over the front end.

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

I set the high idle rpms to a rebuild sheet I found online. I will back it down a bit tomorrow afternoon.

Yes, all the degree figures are crankshaft degrees.

By slow on the heat riser, I mean if you pull it all the way back and let it go, it will hang at half open for a second and then close. Not as fast as it does when cold, but it does close. Blip the gas and it opens to halfway open again.

I changed the tranny fluid and gasket this spring...and it leaks. So next spring before show season I will drop the pan and fluid again to fix the leaky pan gasket.

Rear end fluid has never been changed however. That is also on my to do list.

What is the difference between the NGK and Champion plugs?

Y'ever find those numbers at the top-right-front corner of your Holley 1920?
Sounds pretty normal; good idea to give both ends of the shaft a shot of this stuff (do not substitute—despite the generic name, it is completely unlike any other penetrant).
Go fetch Chrysler's own really nice double-seal, reusable rigid pan gasket № 4295 875AC. A nice, sturdy new deep pan with unwarped rails (if you need it) can also be had as Chrysler part № 52118 779AD, and they even include a spiffy magnet to catch metallic shavings. (Note if you have a trans fluid leak from the left front corner of the pan, it may actually be coming from the shift shaft seal above the pan rail)
Better design/lower arcover voltage for surer ignition, much better materials and build quality, much longer life.

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

Finally got the numbers off the carb. The number is 12R-4285B.

No, you're looking for a different 4-digit number, one that doesn't have "12R" before it.

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

Damn guess I'll look for it again when I get home. Otherwise so far the car has been running pretty well after the adjustments.

The number is here on a pre-'71 1920 (green box):



The number is here on a '70-'73 1920 (green box):



Both types were made for '70; the California carbs are the late type and the 49-state-plus-Canada-and-export carbs are the early type.

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

Alright finally got a break from the rain long enough to run to the garage. Here's what I found:

3620
4656

It looks just like the carb in the second picture.

4656 is the relevant number. That's a 1971 225/automatic carb.

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

Awesome that's what I needed to know.

I pulled a few plugs just to see how it's been running and they are all rather sooty. I will be switching to the NGK plugs soon, but don't want to assume that they will just magically burn cleaner. To me the black sooty plugs indicate a rich mixture at cruising speed. Maybe I should look into dropping in a #59 jet at some point to see if that leans it out a tad at cruise RPMs.

That would be correct if you were cruising along fast enough to be running on the main jet for a few miles, and shut down engine down at speed coasting to the side of the road then pulled a plug for a look-see.

Idle and transition (that gray area between curb idle rpm and full on main jet supplied fuel) circuits are in play during slow operation or idling. So if your last few hundred feet or more of driving is slow, low rpm running, say below 35 mph, pulling a plug once in driveway, you are reading idle/transition circuit mixture which is controlled with idle air mixture screw.

Now it could be both circuits are rich, or choke is not full open (probably not the case here). Idle circuit contributes to main jet circuit once up to speed (both make contribution at that point and are added together), and if jetting is off a just a little, can correct a lean jet up, or richen up main jet circuit under when getting into main jet. At wider throttle openings idle adjustment becomes less of factor.

Enrichment adds additional fuel to main jet circuit when demanded by driving conditions, generally it is one set flow rate with no adjustment. Accelerator pump shot is temporary enrichment to bolster correct A/F mixture during temporary lean condition when intake manifold sees blue sky, and enrichment circuit comes on line.

Start with adjusting idle circuit using vacuum gage look for highest reading, than move on to main jet. Pump shot probably is not adjustable on your carb. One thing to keep in mind, if throttle stop is keeping throttle plates open too much at idle, carb will be idling on transition circuit making this circuit lean thus an incorrect idle air screw adjustment . This problem can be fixed by first adjusting throttle stop so less of transition slot is exposed. Idle rpm can than be adjusted with base a timing adjustment, and then readjusting idle mixture screw. You may have to Ping-Pong back and forth between timing and mixture adjustment before hitting that sweet spot.

Next assess main jet contribution; rich lean or right on by driving 40 mph for a ways, than killing engine coasting to side of road, and pulling plug. (this is right out of the Holley tech YouTube series)

Carb tuning can take a bit of fiddling around before it all becomes a harmonious balance. Chances are once you get the idle circuit correct, and are using stock main jet, with correct float level set and new fuel filter, all will be swell. All this contingent on no vacuum leaks.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Wjajr is right, but if I understand you correctly you've got a № 61 jet in the carburetor (a "612", which is a middle-of-the-spec № 61 versus a low-end-of-spec 611 or a high-end-of-spec 613). That is not the original jet in that 1920 carb—the 3-digit jets didn't exist at the time—and it is much bigger/richer than the jet that came with that carb, which was a № 55. So yeah, you're going to be running rich.

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