If using a torch, you DON'T want to directly heat the bolt itself as that expands it and makes it tighter. Try heating lightly around it but remember that you're dealing with sheet metal so be very careful to not get it too hot. Of course, heating and cooling the bolt several times could help loosen it but don't try removing it when it's hot.

Not to put too fine a point on it but if it leaks so much that it must be checked constantly, then it is ready to be rebuilt. If no leaks or only an occasional drip, then no need to worry and check it so often! It really seems extreme to go through all this work when just looking on the ground for a puddle of oil will tell you that something is seriously wrong.

Incidentally, you posted this in the 1955-1956 section.

It's also not a limousine as advertised. It is a long wheelbase sedan.

If they are the non-flush type, they will also be proper for 1951-1954 Henney-Packards.

As far as I know the castings are quite different so you couldn't simply add a V8 dipstick to a 1951-'54 Ultramatic and I doubt you could use the V8 transmission itself either as they probably have entirely different bolt patterns. Possibly you could install a late 1954 Gearstart Ultramatic but it would mean also replacing the complete steering column and all linkages including the throttle rod to the transmission.

I don't think the Doorsills LLC is still in business. That is according to Yelp.

I'm still looking but the only photo I've found so far was of something else with the fan barely visible. I'm sure I have one somewhere but the car is 550 miles awau so I can't just go take one until I'm there next.

I have a multi-blade flex fan in my 1954 aluminum-head Patrician which I am going to soon replace with a stock fan. It works well and keeps the engine cool (a bit too cool in my opinion) but the main reason I'm replacing it is that it's noisy. That is, you really can't hear it when driving but with the hood open, the fan has a distinctive creak over the sound of the engine itself.

You may find the same issue of running too cool if you use an A/C radiator in a non-A/C car so why not just re-core your stock radiator? Unless you do a lot of slow desert driving, a thicker fan will not be necessary.

The V8 radiator has the lower inlet on the driver's side while it is on the passenger side for the 1951-1954. As Howard indicated, the 1951-1954 are basically the same size and shape but somewhere in there the mounts were changed to add the rubber pads but I don't recall exactly when that happened or if the change also caused a change to the mounting flange.

That said, the A/C cars had a thicker core and different fan with more blades so if yours is factory A/C, you'll need to be sure you use the proper core. Too much cooling is nearly as bad as too little so it's important to get one that matches what was engineered for your particular engine and accessories.

I would probably soak whatever is left in PBlaster for a week or so, then at least try to drill them out. The PBlaster and heat from the drilling, along with an EasyOut might be all it takes and will save you much work. If that fails for whatever reason, that would be the time to consider replacing them.