Don't know where you are getting your info,parts for a 5.0 or 302 Ford are just as common as SBC parts there are plenty of Ford sites on the web full of classifieds,pick up a Summit catalog and see for yourself check out Edelbrock or Trick-Flow head prices.So here a a few simple facts,the SBF can be put in a '54 with over the counter mounts as stated above,a SBC will have to have mounts fabbed,your Ford uses a Front sump oil pan as do SBF Fords they used front sump pans in Mustangs and Broncos for years ,SBC's are rear sump will not clear your Fords crossmember and steering linkage,SBF has front mounted distributor,SBC's are rear and an HEI will interfere with the firewall so you will have to use a small Mallory or MSD with a small cap,location of SBC's oil filter requires a very short filter to clear frame in Ford.no clearance problem with a SBF.Then there is the steering box clearance,but if you really want a "belly button" motor have at it.