As far as I know, all the gasser trucks had a clip on the frame, box mount, or fuel pump protector box back by the front of the rear wheel on the passenger side, and the filter had both inlet and outlet on the top of the filter.
The diesel 720 had the pre-filter on the firewall in the same type clip with both outlets on the top of the filter, the hose then went to the lift pump, then to the main filter which then went to the front of the injection pump.
the clip was there but the filter was not in it. i think it was knocked out. would be no surprise as winter roads can knock anything underside out thats not bolted down. and some stuff that is bolted down. there was a new fuel filter in a drawer when i bought this so its what i used. went for a drive and noticed from cold (-4c) it started right up and ran without me having to rev it for a minute. and it seems to drive smother than before. if it stalls out again i will check the relay above the fan motor by the passenger side kick panel. i read about that gem in another thread. the one not in any manual. but i think the filter was the problem.
im sort of a beliver that the general rule is a fuel filter is a fuel filter is a fuel filter so here is a pic of the one i am currently running. it looks a lot like the stock one i had on my 86 dodge minivan. that had a 4cyl too.
again, thanks for your help. i started a thread about things i can get rid of under hood if anyone wants to check it out. i think im the only guy whos threads start with 720 motorhome. lol.