Is it OK if we call you Jay???
I have slowly been building a mental picture of your truck and somewhat of an idea about you and your capabilities as limited by, knowledge, skill and available equipment and facilities. However the part about you still needs a lot of filling in. Therefore I am doing a lot of guessing at this point. If you really want good advice from the membership here you have to fill us in on a lot of the missing pieces. First we need a lot of pictures of your truck and what has been done to it. Not just pictures of the truck itself but get under it and under the hood. get them posted here on this thread, not in the gallery unless you already have a gallery someplace else. Remember, to post pics on a gallery here they have to already be hosted online someplace like photobucket or myspace.
Next we need to know some things about you and what you have to work with. Answer the following questions:
1. Do you have a garage to work in where you can work on a level floor and have enough space for your truck and another chassis beside it?
2. Do you weld?
3. Do you have a welder and if so is it a stick welder or a MIG? If you have a MIG does it have gas or is it just a flux core machine?
4. Do you have an oxy-acetylene cutting torch?
5. Do you have any kind of grinder?
6. Do you have a compressor and air tools? If so what air tools do you have?
7. Do you have an engine hoist?
8. do you have at least four or more jack stands?
9. Do you have one or more hydraulic jacks?
10. Do you have a good selection of hand tools?
11. Have you ever done anything like this before? If so tell us about it.
12. Are you willing to invest the time and money required to do what you want?
These are just a few of the things we need to know to help you out with your project. According to what I have read from you so far there are so many unknown variables, that all we can do is just throw suggestions at you or tell you what some of us have done. If you are looking for a fixed and guaranteed solution you are going to be greatly dissapointed because there sren't any. It just doesn't work that way. Basically you just start with a plan based on what you want and what you are capable of doing. then you find the basic parts you need to start with and work from there. The thing is that you will not be able to just go out, collect a big pile of parts, come home and throw it together in a weeek or so. A lot of builds you see here are taking or have taken years. Are you willing to commit to that sort of project?
Here is what I think I know so far... If I'm wrong then set me straight. You have a '51 F-4 sitting on what you think is a Ford Galaxie rolling chassis with a 289. Apparently it was a bit of a hack job I gather. What I don't know is what generation of Galaxie the frame is from, what was retained of the Galaxie rolling chassis, what was modified and with what if it was. At this point I'm guessing somebody just more or less forced the '51 down on the Galaxie rolling chassis and hacked whatever was in the way out. Chances are you don't have anything left of the original cab mounting left on the cab and I would venture to guess that they have hacked up the cab and bed a good bit in the process. If I'm right you are goint to spend a lot of money just to get the cab back to the state where you can get it mounted on the original frame you bought. If you did and you still want to go with the 289 and whatever tranny you have, you will have to modify the old original frame. If you are dead set on using that 289 I think you would do well to look for a Ranger circa '95 because that is going to be about the easiest to put that engine in, You probably can get stock engine mounts from an Explorer to mount it. Otherwise you will have to do some good design and fab work.
I have just barely scratched the surface here on telling you what you need to do and I could be way off on several points because you really have not given us that much to go on. So, first get us some pictures posted here on this thread. Then if you are up to the challenge we will help you get through this. You need to understand that we are all different, we have different ideas about doing stuff and that our answers regarding choice and opinion WILL NOT be the same. At some point no matter how much we tell you, you will have to do some thinking and make some final choices. there will be times when a choice or decision just doesn't work out and you will have to take a step back and do something different.
Here is a link you should look at. This is to a Pull-A-Part yard around Charlotte, NC on the NE side right off of I-85. That is about as close as one as I can find for you.
http://www.pullapart.com/Locations/LocationDetail.aspx?locationId=7 You can look at their inventory online. they have a fixed price list and you won't find a set price for what you need. You can get them to quote a complete rolling chassis by special request. Your best other bet is to watch for people selling a whole vehicle that you need the chassis from. Usually this is the cheapest way to go. You get what you want and sell off the rest or scrap it. People will sell off these things cheap if they have a serious problem or have been wrecked. You don't need a title so that will work in your favor too.
I realize this is alot to digest for you but if we get through this part we can all do a better job of helping you. One major thing I see here is that you are not quite sure what you want to do.
Later Man...