Here is a reply to a similar question recently answered by Dick Spadaro. Dick is a very knowledgeable Ford guy and vendor. Google Dick Spadaro auto parts to get his number.
"Unless you are absolutely concerned with the correct spring shackles for restoration purposes and have access to correct tools you should avoid using stock OE design shackles for a driver vehicle. Stock shackles require the bushings to be pressed into position, that doesn't mean hammered in, so unless you have access to a 30 ton H press the simplest method is to replace your old worn out spring bushings is to use the newer Hot Rod style urethane bushings. These can be easily installed by hand and eliminate the frustration of the OE press fit. 95% of the people looking at your car wont know the difference anyway"
John