I've had friends do both biodiesel and WVO conversions on older diesels, including one 7.3 van to WVO. You need to change out _all_ fuel line. If you miss some, it will eventually break down and clog.
The WVO needs to be filtered, which involves multiple containers and pumps.
The long term report on WVO was that while it worked, having drums of gross stuff sitting around in (a cramped bay area) driveway wasn't wonderful.
'99 EB ex ENG KSWB news van, low rent 4x4 conversion (mostly fixed by now), home built interior.