Ford 4.2L V6 Questions

Just bought a 97 F150 with 4.2 v6, has 105000mi, Heard some horror stories about this type of
motor. Guy I bought it from had the coolant in exhaust prob, but got fixed on
warranty before motor blew up. Still has 180 psi on all cyl. Only issue is he was adding 1/4Litre(approx) of oil every month or so, not burning blue and no oil
patches under vehicle. Mechanic said he probably used a heavier than specified
oil and the vlv seals might be leaking a bit any cause for concern, any easy fixes.

Also what is the specified grade of oil for this motor, (did not get owners manual)