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Well today I will attempt to remove the valve timing cover which is no easy task, but things point to the cam gear to perhaps being one tooth off. My vacuum is quite low and goes lower as the rpm are decreased to almost 12 or 15 instead of 18 indicating late timing. Also took compression and all cylinders are low but even. This should not be, with new rings, valve grind, etc not long ago. Will post of what I find. Sure hope I am not not spinning wheels.

Somebody else chime in here and tell me if I'm way off-base, but it seems there has been quite a bit of 'post chatter' of late, about cams being 180 degrees off, a tooth off 'jumping a couple of teeth', and so on. To me, this sounds like bunk. Anybody with half a wit about them when they're assembling an engine would know how to line up the marks and install the chain correctly. If a chain is loose enough to 'jump' cogs, there are other, way bigger fish to fry with the engine's condition than fussing with the timing. What is described here sounds more like the distributor wire sequence is out by one position. If a guy gets #1 piston to TDC ON THE COMPRESSION STROKE, sees where the rotor is 'pointing' and which distributor cap position it corresponds with, and then traces each wire in the correct firing order to each plug, the engine should be 'in range' of the correct timing, enough to run. It can be tweaked by various methods (described at length by the many pros on the site) from there to optimal performance. The timing cover can be removed and the chain/cam checked, but that is A LOT of work, and going through the foregoing first is a lot less invasive. Chris.

Chris hit the nail on the head. If the engine was running properly and suddenly it isn't, it is very unlikely that the timing chain could have jumped a tooth. If the chain is that worn, then it's time to pull out the engine for a rebuild. More likely electrical or ignition, fuel pressure or even bad fuel.

The engine stalling when the throttle is opened very quickly. Could that be an issue with the accelerator pump in the carburetor?

My experience with jumped timing chains is that the engine will be running nicely. Then it fails to restart. The restarting is enough shock for the chain to jump. Of course this is with an engine with a badly worn chain and nothing else being changed before trying to restart.

I had a similar symptom recently. It turned out to be the coil. Which I found by reving the engine to a slight miss and found by using a harbor freight spark tester which hooks to the spark plug wire the spark was disappearing. I also found condensers out of spec. cause simular problem.

I know in more modern engines, the top gear can be made out of a composite material to reduce noise. When these wear excessively, and the timing chain stretches a bit over time, they can 'jump'. I even saw one back when I was in the taxi business, where the top gear became so worn, it actually 'stripped' and the chain ended up 'freewheeling' with valves hitting pistons and the engine was done, but this was a cab with half a million miles on it. Packard's engines with their steel gears and robust, multi-strand chains should not be vulnerable these kinds of timing issues. Chris.

I like Marston's suggestion....

I see the Motors Manual says a low vacuum reading at idle can also be not enough clearance on the valves. But with hydraulic lifters I wouldn't think that would be your problem....

Here's what the 49_Carburetor Training Book says.
https://www.packardinfo.com/xoops/html/downloads/49_CarburetorTrainingBook.pdf
Wes

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