I agree the best long term solution would be to pull the motor, go through it, rebuild, and reinstall, but that's not my mission here. I drain out what looked like Marvel mystery oil so things might already be messed up. I'm only trying to move the loose sludge out of the pan to put new oil in so it doesn't clog things up worse. I'm not worried about the hard stuff that kerosene won't touch or further up in the motor. I only need to assess if the motor runs or not, not how well or what's best. I've not decided whether to restore, sell, or do something else. Alot hinges on if it runs as is or not. There's a fair probability it won't go or it'll be ugly (rings, stuck lifters, etc.), so why sink more time/work($) in to watch that? I can use that money for rebuild/new. If it runs, it doubles it's value.

It's sad that it costs more to repair a tank than you can buy a new one for, if one could find a new one that "fit".
Might needs some bench engineering on this one. Seek out a new replacement tank that's close and retrofit or if the local radiator guy can split it, I/he might be able to blast it and get him to put it back together and then seal it. If I resto mod it, I might do custom SS or aluminum.

As someone said depends on what end, but there's raw fuel or fuel mixture entering either the exhaust and the temperature is high enough to touch it off or it's backing compression through the carb as it fires. Typical causes; timing, misfire(no/intermittent spark - spark plug, bad/lose plug wire, cap/rotor, coil), or valve(s) sticking.
If it sits alot, the oil drains down and worn or gummy things stick. A dead cylinder with bad rings will send gas down into the oil and it can end up anywhere then plus thins the oil. Go through the spark electrical, check the timing and oil for gas smell/cleanliness, and run some valve ease or engine treatment.
Combined with blueish smoke, to me, it's pointing to possible a ring issue. Compression test is in order.

Any info on what they charge for the tank ReNu? I see WV is the closest to me.

With no filtration, I was not surprised to have to poke out some of the motor oil. I'm preparing for the kerosine flushes next(i.e.not running). But it got me thinking how good the oil pump is? I saw it's a gear pump, and it's old timey all metal, so it'll work as long as it turns and the stuff can get to it. But what's the experience tell us? Rebuild regrets?
The gas tank was no surprise either. The issue everyone similarly faces is how to best limit the damage. Is it best to send your problem to someone else? Do it yourself?
or what? Exchange vs repair? Recommendations on kits? I'm sure that's a, it depends, question so I'm saying mine is average, sludge and rust, but overall the tank is very solid. I'm whisking off the sending unit Monday, so that's covered. It was similarly rusty and had a large wad stuck on it so it always read empty I'm sure, but the wire was gone.

Thanks again. I'm pretty(99.99+%) sure I got it right, after some more digging. I found another non-Packard source and they made the same "mistake" on the pump. I'm a ChemEng. and we live under vacuum, so that was the easy part. Whomever rerouted this tubing must have worked in a maze most of their life... I don't know if they just gave up, or it actually ran like that... I'm sure it wasn't going far with what I took out of the fuel pump sump. You could have repaired a good size chuckhole with that wad. Driving in the rain musta been fun.
My fix on the exhaust manifold carb heat riser worked out. It's a bit tricky without removing it but it's a neat solution, if you're tube is rotted off. We do alot of tubing too.

Glad I'm not the only one who ever had this problem. Phew!
After closer inspection, I'm going to connect the line on the firewall to the wiper motor, proximity gives it away, and pump inlet and pump outlet to the manifold. It shows up the most times and makes the most flow sense. And it won't screw anything up, if it's wrong. If there's anything later, I can add.
My 30+ years of eng'g in hazardous chemicals have taught me to seek out other opinions when things aren't clear and to demand complete and thorough documentation on systems. 80% of all problems I troubleshot came down to not being run at design conditions. The rest usually weren't designed right or unforeseen/unresolvable.
Check, recheck, and check it again. Eliminates 99+% of errors. So far, the one I assumed and didn't check was wrong...

I looked at the plates and service manual and they rerouted the vacuum. I guess the pump wasn't working. I'll have the pump rebuilt soon and need to get tubing and plumb up. I've not yet got a real solid idea on the correct routing.
The booster pump inlet runs along the block and the end with the hose was not connected/plugged. The pump outlet wasn't connected.
The plate and service manual shows the pump out going to the intake manifold and the inlet extends past the picture behind the motor. They had the wiper motor connected on the intake. So if I connect pump there then the wiper motor needs vacuum source. Does the inlet go direct to the wiper motor or are there other vacuum needs/connections back at the firewall for interior/trans/clutch/ etc.? The heater valve is missing and there's a tube coming up there which might be the wiper connection or something else.
Is there a better routing source or schematic? Am I on the right track or not? Thanks.

I'm all confused. That broken tube I was thinking about was on the exhaust manifold. Need a break.

Thanks guys. This's like doing a 1000+ piece puzzle of a fuzzy picture, you're never sure about some pieces. Once you've done it/seen it, it's easier.
I thought I crossed somewhere that said oil filter was an "option", which sounds outrageous, but the specs list this as solid lifter which fits no filter. But @ 10 cents a quart, who needed one vs frequent changes.
I'll rebuild the pump and see why vacuums not in use as part of fuel system check out. The vac tube that goes into the head, appears to be broken/rotted off the stub but as you say, may have been connected via hose, but there's not much stub surface and two different OD sizes making a good vac hose connect improbable. I was going to try to take out the stub and/or rebraze or make a new end. I dont know why I couldn't tap for a tube fitting? But that's another day.
As someone suggested, i.e. muffler shop, I've just about made repairs to the water outlet via exhaust bell reducers welded to my original base. A 2 1/2 to 2 then 2 to 1 3/4 works nice and give the rite height. Avail at most auto parts stores. Got a few leaks to remove yet. That should get me through start-up. It's one thing to strongly stick thin metal together and another to make it pore free. I think my MIG welder is OK after a new regulator. Trouble shoot the TIG next. Waiting on the air compressor motor, so it's a slow slog.
That air cleaner decal I mentioned is correct and looks nice.

Is it correct to NOT have an oil filter canister? One of the site pix shows it on the six over the generator but none on the eight(?). I'm not sure if mine is missing or it's a delete option.
There's a two stage pump on the fuel (?original?) and one side is not connected to anything. I suspect someone put this on from something else, because they ran fuel hose and in-line fuel filter but I haven't really had time to explore this system.
I didn't find an assembled view of the 288 motor yet, if someone can point me.
ps: motor parts list shows 4 head water outlet part numbers but one gasket number so it's luck of the draw what you got if your's not listed