Not a 450 its a E350 dual rear wheel ambulance model. They came from factory with a stabilzer that I believe should have been on every econoline. I got the stabilizer itself from O Reillys Auto Parts, read above posts for details
andrew
The 450 may use the same stabillizer but I think it has a bigger chassis, I just know what does work.
All the parts used in this are factory Ford parts except I used the Oreilly stabilizer. The brackets bolt straight on with no drilling.