Bendix 6.75 vacuum brake booster

[Sidetrack]

Ok Guys need ya to put on your thinking caps for this one,

I've got what is listed on the parts diagrams here as a 6.75 Bendix brake booster, which from what I'm reading here was standard on f-350 models in 66.
First thing that strikes me odd is it isn't mentioned anywhere as an option on the 250, but mine is a camper special so I'm guessing some things that aren't standard on any other model might be on mine.

When I went to the local parts house and looked up the parts to try and repair this thing the only model it showed up for was a 60 f-100. Ok after working in the motorcycle industry for a few years I know that mfg's recycle parts across the years so this didn't suprise me too much either, but where I'm running into trouble is finding any re-build kits for it...I'm pretty sure the diaphram has a split in it somewhere (maybe dry-rot?) because when I press on the brakes the idle raises about 2-300 rpm.

Does anyone know of a source for these parts, I really hate to have to buy a $300 booster when all I need is a $30 kit.