I was thinking of putting a/c in my 68 f100 but I only got the inline six 240 is this going to be to small to run an a/c unit and where whould I get brackets and pullies

 

If a 3-cylinder Geo Metro engine can turn a compressor, surely your engine can. I don't have an issue in fron of me, but look in ads of Hot Rod, Car Craft, or any number of other such magazines. I recall seeing a few ads for companies that make custom brackets.

 

www.bought4less.com can supply the mount and drive , compressor, the whole AC system if you want.