As far as putting the body on a newer frame, that is what my truck is but I had the ownership of both vehicles before I merged them. I could have got a "Builders Title" by surrendering both titles but that would have made my truck a 2009 model subject to safety and emission standards of 2009. I don't know about OK. but in CO the registration and ownership fees are more expensive the newer you get. My title is 1953, I guess I could have used the 1973 title but the truck sure don't look anything like a 1973 and it certainly don't look anything like a 2009.
If the paperwork suits you and the state I guess it is good enough but you will surely have problems if you ever try to sell it.
