The harmonic balancer is rubber mounted and the outside ring can slip. This will give you a false timing setting resulting in exhaust overheating. The change in vehicle performance may not be noticeable. It happened to me once on a trip back to school. The floor seemed hot so I stopped to see what was going on. It was night and the exhaust pipes were glowing red. To confirm, you need to take an old spark plug, bust out the ceramics, and install a bolt into it. Screw the plug back in #1 cylinder. Rotate the engine manually clockwise until it hits the stop. Make a mark on the balancer at zero. Turn it counterclockwise until it hits the stop. Make another mark. Halve the two marks and that should be the timing mark on the balancer. If it's not, the balancer ring has spun.
Yeah, that, and because your ignition is likely points (I don't know if you've converted to electronics or not), as the points wear, the dwell (the time the coil is charging) drops, which drops your timing late. So, you should hook up a dwell meter, set your points at the highest degree of the specification, then recheck timing. If your points are actually worn badly, replace the point set and condenser. If you need help with that, let me know, I have pages on my phone I can email to you for working on points.
So, the points are 14-16 and I set them at around 17 just to compensate for when I tighten the screw down. Fired her up again and she seemed to run a tad smoother and cooler. Little steps here and there for forward momentum. I am going to go back over her and reset her timing again just to make sure.
The balancer has been rebuilt by the damper dudes and they did a very job. I assume that it can only go together one way. That way there is no way to rotate it when it gets rebuilt.
Okay, setting dwell by thousandths gets you in the ballpark, but even seventeen thousandths only equates to 25-26 degrees, whereas you want to be in the 29-31 degree ballpark, based on the actual spec. Hence, why you need a dwell meter, as well as a timing light and vacuum gauge, for care and feeding of your Blue Oval.
I have all three and am going item by item hooking the em up and checking them off. It will be a awhile but headed that way.
Been awhile so I thought I would update the forum. I still have Betty here is what I have done lately. I replaced the driver side rear footwell, pass toe board and replaced the top of the pass front rocker panel. After I rebuild the O/D in my A, replace the flooring in the house, and solder up the air compressor lines I will get back to dropping in the pass front floor pan. Then replace part of the tunnel and move to the pass rear floor pan. And then back to the drivers side floor pan as I installed it incorrectly-didn't realize it at the time. Then she goes to the shop for mechanical work and then a whole lot of other things before I can get her on the road next year. Well that is the goal........ Mike