I've got a 1960 American LaFrance pumper on a pugnose GMC chassis with the 401 V6 and a Clark 5 speed. I'm planning to remove the driveline-mounted fire pump and replace it with a 3-speed Brownie to get 15 forward speeds and 3 reverse gears. I'm going to remove the fire bed and install a commercial 5th. wheel and a gooseneck trailer hitch and make it a heavy duty tow vehicle.
http://www.hunt101.com/data/500/61_GMC_001.jpghttp://www.hunt101.com/data/500/54_GMC_002.JPGThis one is a 54 GMC 630 that I drove from Tennessee to Kansas City for the 2015 get-together after Ed Pruss broke down near my farm on the way to Denver. I patched up a leaky head gasket and fixed some pretty serious brake problems. Ed flew to KC a week later and drove it the rest of the way to Colorado. It's got a 503 cubic inch inline six and a 5 speed OD trans.
Jerry