The best frame for your '51 Ford is a '51 Ford...
If you MUST have front IFS there are hundreds of options available from MII kits to sub frame grafts to bolt on kits.
A frame swap is a MAJOR deal... I have purchased about 5 F-1 and F100 trucks over the years that were owned by well meaning guys who attempted a frame swap and gave up... usually only AFTER scrapping the original.
My '56 F100 has a B-body MOPAR torsion bar front suspension kit on it. Bolts on...inexpensive... and they ride great. Dwight Bond in Gibbon, NE used to build them and now his brother does...
BTW... sorry to nitpick but restoring a vehicle means you are bringing it back to all original condition... what you are doing is hardly a restoration.