Depends.. Some lincolns did come with an 5.0 HO. I think its was the Mark series or something like that. If it came out of a lincoln towncar or a continital it is a NON HO 5.0 The differance between the non HO and HO -
firing order, injector size, throttle body size, exhaust manifolds, camshaft, heads. I'm sure there is more but that is most of the important differences. The block and the crank, rods, and i think pistons are the same. If the engine is complete, look at the injector color- if it is grey (14 lb) its non HO. An HO has orange (19 lb) injectors. Look at the spark plug wire routing to figure out the firing order. Non HO is 13726548
HO is 15426378
Basically if it turns out to be an HO it is the same as a mustang 5.0 and I would get it.
The non HO can be converted to an HO but it can be a pita to get all the correct parts.
Do a search of the threads here. there is some good info on here about this. Also check out coolcats.com or coolkats.com (never can remember the spelling) They have a great tech info section on the NON HO to HO conversion.