What do you guys think? 

 Then reconnect the vac line and adjust the engine RPM down as needed  using the adjustment screw on the side of the carburetor linkage.  You always set timing with the vacuum advance disconnected.  

That leaves carburetor, or ignition...

Does this misfire happen only at idle? Or at speed? If you cruise steady flat and level 45 mph in 3rd, does it misfire then? How about wide open throttle? Or just idle.

Lean engines act badly. Rich engines are stupid and smooth and sluggish, drunk on fuel. So Back out the idle mix a turn or more see if it improves. If not, move on to ignition.

Is each electrical connection bright clean shiny metal tight enough to tug on, hard? No wires wrapped around screws with a nut and no washer? Crimped connectors you can pull the wire quite hard and it should not come out or wiggle.

Is the electrical connect to the points one of those craptacular "slide in" types? Or does it have a stud with a nut and captive toothed lock washer? The slip-on kind are CRAP. Blue Streak used to be good, are they any more? Dunno.

Wiring has to be good all the way back to the battery (power source). 

Spark timing can do weird things and even misfire, but usually there's other weird side effects. One way to ball-park it is to loosen and rotate the distributor 10 degrees one way, see if it improves/worsens, back to 0, then 10 the other. None of these are fixes, but tests. When all's well, it will definitely change RPM, but not much more. But if somehow timing is really off, making it worse might tip it over into bad misfiring or something. My estimation is that timing isn't the problem, and that you have an electrical intermittent (if we're taking bets).

LakesideRamblin wrote: Double check or replace all spark plug wires and distributor wire again.  I had this same mystery years ago and a "good" spark plug wire turned out to be bad.  Drove me crazy but an easy fix.

Isnt it better to check first before filling the parts cannon?

This is not checking timing, just using the light it to determine consistent spark to each cylinder. If you have consistent spark, you have eliminated this as a problem without replacing anything.

Takes 15 minutes. 

I went out and bot a timing light and a vacuum gage, I'm happy I finally did it, 107$ well spent. So, following most but not all of your direction from your posts, I disconnected the vacuum from the dist and loosened the dizzy and turned it either way till I found a good spot where the engine seems happiest, but I didn't bother turning the screw on the carb, but anyways, it didn't make the miss get any better so I moved on, (man the engine sounds bad with the new YFA instead of the weber!! It sounded so happy, even with the miss) I used the timing light I bot, a simple inductive one with the flashing light that pulses with each electric jolt, and saw the following.... #1 cyl was pretty steady, maybe even completely steady unless I didn't notice a extra flash or double flash, #2 cyl seemed the same, #3 cyl steady with a extra flash here or there#4 the same as #3, #5 cyl completely crazy machine gun flashing, and #6 lots of flashes but not as nuts as #5, maybe steady but at a double pace, and the coil wire was the same completely crazy machine gun flashing, that's probably normal. I switched the #5 cyl wire with the #6 wire and nothing changed like I thought, and I even swapped out the new NGK plug wires with the super old wires that came with all the stuff for the disassembled rambler parts, and observed the same performance with the timing light. I even thought to see if the spark plug wires might be too close, but they seemed to have enough space apart... I set up the vacuum gage at the manifold and observed a steady vacuum of 20(?) so I suppose there is no vacuum leak according to what I saw, which was nice and interesting to exp.

It was wise to change wires and plugs and to check for separation. The wire internal to the distributor that you attempted to lower was it in the vicinity of the problem 5 and 6 distributor terminals? If so it might still be a contributor to the problem.

Also observe the distributor cam. The lobes the points ride up on should all look the same. I have seen baked-on grease affect the point gap on a certain cylinder.

Anyways, not sure if anyone's following this post anymore, but I'd like to share what solved the misfire... 

At least I think the misfire is solved. 

Anyways, troutwilly suggested the dist cap must be arching and resulting in the inconsistent flashing on some cylinders, and rapid flashing on #5 plug wire seen when the timing light was used. I didn't think I could get a new cap, but after he suggested it, I thought, well, I'll try, I don't think I can get one the dist is so old, but I'll try. And when I did the parts guy was a old guy and he knew where to look in the book under the counter and said he had one on the shelf! Usually the young guys look on the computer and say "no man, our data base system only goes back to 1962..." and for some reason they don't know about the book under the counter.... Kinda annoying.... So I had a new cap, put that on, re organized 5degres btdc (troutwilly suggested I add even more advance and have it at 10degrees btdc, so I did that, or at least guessed, no timing tape or numbers on my balancer....) and made sure all the wires were on right as per firing order, and noticed something about the plug wire for #5.... The blue wire (ngk brand, if your having trouble visualizing this you could google image the ngk wire to see what I describe) and the black end that surrounds the spark plug had separated... It wasnt connected in any way that was sturdy and solid, it was only connected with clear silicone, one time when putting them on I must have wondered if it was on far enough, and pushed the black end too much and it broke the silicone seal that was holding them together....and the blue wire and black end were separated and the black part had been pushed farther down the spark plug, leaving the end of the blue wire that has the exposed wire inside that sends the juice to the spark plug tip far away from the tip of the spark plug..... And the next time I had put the wires on the plugs, they all looked the same, but the number 5 wire wasn't on the plug properly, I felt it and it must have been around an inch away from the tip of the spark plug for cyl #5.... Maybe this was also contributing to the misfire? Anyways, after putting on the new cap, and also fixing the situation with the spark plug wire, I started up the engine and used the timing light and didn't see any inconsistent flashing while using the timing light! The engine no longer shudders noticeably at the same exact time the "chuff" sound occurs, it's smooth, but I do notice the sound is still here or there, I'm not sure if the rusted out muffler is the cause of the sound... Probably not.... But I can't notice any inconsistent flashing while using the timing light on all the plug wires, it all looks to be firing correctly..... So just thought I'd post the results of the mission to fix this misfire. 

If you have plug wires held together with silicone, you need to just replace them. YOu can harvest them from junkyards even, just make sure they're flexible, not cracked, and the boots and terminals are attached solidly. New ones are cheap.

Lots of cars used that distributor cap and that old guy new that, so win win. Even if you don't buy from rockauto.com it's a great source for identifying parts to buy locally, and to see what a reasonable price is.

Tom,

So glad its smoothed out for you. 

I have to ask though, are you setting your timing with the timing light and balancer marks while the engine is running or are you setting your timing with just the balancer at 5* BTDC and turning the distributor so the rotor points to the #1 wire?  I ask because your description of what you've done leads me to believe you're setting it with the engine off.  If that's the case, you need to do it with the timing light and engine running.

And to clarify my 10* advance suggestion; recommendation for most stock engines is probably 6* advanced.  You can advance it more if you don't get any adverse running conditions (like pinging or fire through carb) but I wouldn't go farther than 10* on a stock engine.

Tomj, totally agree on using Rock Auto to reference prices and find part numbers.

With a rusted out muffler you will hear a little huff once in a while as gasoline is not a perfect complete burn (especially carbureted engines)  ever see rally racing videos and the cars back fire out the exhaust?

Nailed that problem, whats next on the agenda?

trout willy- yes the engine has been running while setting timing but I didn't know there was a method to aiming the timing light at the balancer while twisting the dist.

Lakeside ramblr - I'm dying to finally drive this car too after all this work!!! Beleive me, I'm the one person besides you that's dying to know, when I do, ill let you know brother! 

Softbuster-  " what's next on the agenda?" well after figuring out the weld through primer situation, before I even knew about weld through primer I was using regular primer and paint, and watched it get destroyed thinking "huh, don't know what I'm supposed to do about that problem" yesterday I used "dominion seal" brand, and it was a copper type, and I calmly watched the heat from the welder blast it to holy helll, so now I'm going to try and use VHT brand, and go from there. I got lots more welding to do, "crazy fabricating" is what someone told me I will have to do when I weld the bottom part of the cavity, (weird double floor near end of drivers and pass side of floor) while lying on my back under the car outside, welding that close to my face for more then two hours at night was crazy. Hope I don't run into any more problems with the welding department, it's not a easy job. 

Farna- the head was magnetic partial checked for cracks but it was of course cold at the time, you mentioned cracks can be more noticeable when the cyl head is hot... Fingers crossed..... 

-tom. 

Anyways, maybe the timing chain wasn't put on right by the engine builder and the valves aren't in sync? Just looking through my old posts for the sequence of which valves under which rocker arms are the intake and exhaust... 

Rambler valves

int .012

exh .016

hot

FRONT  IE EI IE EI IE EI  REAR

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