Its possible to remove into two originial parts; but after 30 plus years of road grim etc; seem the only way is to saw-all with a metal blade. Theres a roll guide / connector rod that holds and supports the two mounts. That's the only succesful way ; that I know, for which i recently help a fellow member remove one. I recommend purchasing new mounts if funds are avaiable.
Sorry I don't hold a solid answer....
if you are not restoring the truck a nother option is sawzall the old off and buy hockey pucks from a auction, yardsale or ones you have lying around of bought if cheap enough, drill your holes in the pucks and head to the hardware store for bolts
which ones are you talking about. on the radiotor support ones i soaked them in pb blaster and one came off. the other i had to saw off. on the front cab mounts the holes in the frame were so big i just pryed and they poped out. on the back cab mounts i took a bolt that fit perfectly into the hole and hit it with a sledge hammer but mine wouldnt budge so i had to cut them off. depending how much rust yours has it might work.
heres a kit that seems to have everything that gets cut up in removal eBay Motors: Energy Susp BODY MOUNTS ford F-250 75-79 78 77 76 1975 (item 230295687635 end time Oct-26-08 21:14:04 PDT)
Just went through this! Sawed the radiator & front cab mounts (real rusty). For the rear mounts; after the cab was off I used an angle grinder and cut the top metal plate section close to the bolt hole, the top popped right off and the bottom half fell out! Good luck!
Perfect, thanks for the responses, i'll begin cutting today. I just didn't want to do more harm then good but ripping into them. Thanks for the replies as always i'm glad i checked in with the forums...
Here's another question, since i'm frame up restoring the truck is it easier to replace the ball joints with the axle housing on the frame or would it be easier to remove the front subframe and crank on them from there.
I put an impact wrench on the bottom nut and worked it forward and backwards and hit it with a BFH until I broke them free. I was able to save all my hardware from the cab mounts. Once I finally got them free I found that all the metal that the rubber mounts were sitting on were completely gone, so I ended up replacing the front cab support brackets, the rear support were fairly pitted but were usable. Check out these pics: