After talking to my more experienced neighbor, he said that the most important part of selecting a donor vehicle for you project truck is to make sure that the wheels aren't going to scrape on those narrow 1946 wheel wells. I measured the inside to be 19'' on my 1946 cab. I was measuring a 93 f-150 at the junkyard the other day and it seemed to be a close match, much closer than my 73 F-250, which was like 23" and would scrape for sure. Just trying to make sure I buy a junker thats going to work out for this project. If anyone has experience with this please tell me what you did.

Also, I was wondering what the distance between the axles is on a 46 ford. I acquired this cab from a huge truck, so I have no way of measuring that distance. It would be nice to not have to cut the frame at all on whatever donor truck i buy. I am planning on turning it back into a regular pickup with a reproduced bed. If this ends up being a fiasco I might have to settle for a flatbed...

 

If you are going the frame swap route, look through some of the threads on here, there are a few going right now regarding suitable donor frames. You will have to do some work to make the cab work on the donor frame. There just isn't a simple drop and go swap out there. Look on here, you will find out which frame will work best for you so you can be cruising in your truck much quicker.
Oh, and the wheelbase on a '46 1/2 ton is 114"

 

I just ran out to the garage to measure on my frame. Its fairly open since I have almost everything off right now (cab and most of the engine are still on).

I put rims from an 80's 1/2 ton on my truck so I could roll it around. They have 235 75R15 tires on and fit under the front fenders well and seemed to give me plenty of clearance on the box -- but I had no rear fenders at the time so I cannot verify how they fit under the rears.

Front tires -- inside to inside is about 50.5" outside to outside is about 67.5" This measure might be a little off since the toe in is a little off. Front wheel mounting surface to mounting surface is about 60-61" (I just estimated this through the wheel and tire). Outside of frame rail to outside frame rail is 32"

Rear tire inside to inside is about 52", outside to outside is about 68.5", mounting surface to mounting surface is about 60-61". Outside frame rail to outside frame rail is 34". The box is about 50" wide.

Front to back wheel base is 114" for the 1/2 ton truck, I think mine measured close to that.

I got a 9" differential out of a 1/2 ton truck -- I think it was between 68-72 based on the brake size. I didn't actually see the truck. It is supposed to bolt right in, so I would guess that the '68-'72 1/2 ton rear frame matches as well. I don't know how the front works though and I don't know the wheelbase. In '73 the rear differential was increased to 65" for the wheel surfaces (I think it was 65" but it was increased) so newer than '72 will definately need a lot of work to make things fit. If you can't find a '72 to do some measuring on you might go to their forum and ask -- it cant hurt.

I think my measures are fairly close to start with, maybe someone can give you what the standard measurements are. It does leave a question on my mind though.

The guy I bought my first '46 from had restored a '48-'50 (don't remember for sure which year). In talking with him about his restore / my new truck he said that the front wheels don't track with the backs. My measurements put the front and back really close, does anyone know if Ford changed the front wheel spacing for '48? I was guessing on my truck that it was going to be about 65", thinking that in '73 when they changed the rear to 65" it was to match the front. Can anyone verify this?