would love to get a WW2 era jeep, possibly a a Willys MB or a Ford GPW.
I can share a few experiences regarding jeeps.
I owned a 1942 Willys MB. A previous owner (one of many) swapped in the F head 134 in place of the flathead 134 originally installed, along with a T90 BW transmission in place of the stock T84. To allow hood clearance for the F head under the low hood (bonnet, in UK parlance), the owner had made a metal scoop to clear the carburetor and air cleaner, which was the offending high assembly.
I tried driving some CJ2s, and found that the F head definitely had more power than the flathead 134. However, both of these engines are very old-fashioned, with heavy rods and a heavy crank. It takes an act of Congress to get the either of them to rev up, compared to a modern engine.
The military jeeps were the only ones to have a full floating rear axle here in the USA. After the War, jeeps downgraded to semi-floating rear axles. The nice thing about military full floating rear axles is that the rear hubs are identical to the hubs on the front axle, bearings and all. This allows for good wartime logistics, but it is also a boon to jeep operators. Remember that jeeps were not intended for long service lives. They were expendable, cheap war vehicles. Very little money was put into the metallurgy of jeeps. Axles were/are notorious for breakage on these old jeeps, and a full floating rear axle means you can still drive the thing when a rear axle shaft snaps.
Speaking of metallurgy, the frames and springs of old jeeps were also very prone to breakage and cracking when put under long service. Another joy of jeep ownership!
Then there is the Ross steering gear. I will admit, they are easy to repair, as I did rebuild mine. However, they are prone to quick wear, and they are reversible: one can break a thumb when hitting a rock with the front wheel, unless one learns to hold the wheel with just fingers and NOT wrap the thumbs around the wheel rim. A quick jolt on the front wheels can cause the steering wheel spokes to snap a carelessly wrapped thumb in an instant. Many folks here in the USA convert to later GM recirculating ball steering boxes for this reason.
I also owned a 1966 Wagoneer. As far as climbing goes, it would climb any hill that my jeep would. Of course, it was much wider, so it didn't negotiate narrow jeep trails as well, nor would it turn as tight of a corner. But it would climb just as well as my jeep. I recall one time, when going to get some wood that I'd left up a hill side (we heated with wood only in those days, I proved the climbing ability of the jeep. Earlier, I had driven a borrowed 3/4 ton Chevy 4x4 up a slash cut road to the top of a mountain to get some wood. I had to chain up all 4 to make it through the snow. Several weeks later, I went up the same road with my Wagoneer, no chains, and with less trouble. It would definitely climb.
It had the Rambler 327 cu in V8 engine (not the same as the Chevy 327! This one was derived from the Packard design V8 of 1955.) The engine was great, as it had loads and loads of low end torque and would pull like a mule. The transmission was the Borg Warner T89, a tough gear box that shifted quite well.
Like earlier jeeps, however, the bodywork was not very good. The front drive shaft was also a weak point.
Up until the early 60s, jeep pickups and utility wagons used the 226 cu in flathead 6 made by Continental. This was the same 6 used in the Kaiser automobiles. In my youth, I rebuilt many of these engines, as they were commonly used in lift trucks as an industrial engine. To be blunt, they are a poor automotive engine. They were intended to be cheap, but durable motors, however in automotive use, where constant speed changes were necessary, they didn't hold up well at all. Furthermore, they had problems with head gaskets. I always took my time installing the heads to them with care, but I did have to make a number of service calls on motors others had built. These are motors to steer clear of!
My Dad was in charge of the battalion motor pool during the second half of WW2. He knew quite a bit about jeeps because of this, and his expertise was very helpful to me. Since his unit made amphibious landings in North Africa, a bunch in Sicily, two in Italy (Salerno and Anzio) and one in France, Dad was pretty up on how to prepare a jeep for this duty, by extending the air intake up the windshield post and the exhaust, as well. They packed the outside of the distributor and spark plug wires with putty.
Dad's fellows were a bit different from the normal GIs, who went through captured towns looking for wine cellars. His guys looked for machine shops. They were mostly Hispanic guys from Southern California who had raced midgets before the war. Once, Dad said they found a machine shop that was bombed out with an intact planer, and they got a bunch of guys to turn the flat belt pulley while they planed the head of Dad's personal jeep. It only ran on AV gas or captured German AV fuel. Dad said that it would twist the speedometer past the 270º of 0 to 60 mph and back around to 20 mph, at which point, it couldn't be kept on the road. He had a lot of respect for jeeps. When he left his occupation duty in Salzburg Austria for the preparation to invade Japan, one of his guys was swapping a German Ford V8 into his jeep.
So, that's my stories about jeeps.