As I understand it, the Windsor was first imported for Falcon from '67 to '73, then replaced with a locally produced 302 Cleveland. There were of course 351 versions of this engine. When the V8 was reintroduced after an 8 year absence in 1991, the Windsor made a comeback with a modernised, lighter, fuel injected (etc) version that still had a lot in common with its predecessor.
Anyway, for a V8 conversion for an E-Series car, I wouldn't consider anything except a late model Windsor. These will get past any emissions tests, and stroker kits are available if 5.0 litres isn't enough.
But - and this is a big but - if you're after outright performance, a proper rebuild of your six cylinder engine, a forced induction kit, and appropriate driveline upgrades such as a diff replacement will get the most performance for your dollar.
Jack Travis, E-Series Acting President
1989 Ford Fairmont Ghia turbo/GL replica (underway)
1994 Eunos 800M
1990 Ford Laser S