It's been in the family . it was bought at a county equipment auvtion in 1976 with 28,000 mile's on it so if the engine was replaced it was done with very few mile's on it.It's an AMSOIL baby sence the late 90's. . . it get's asmoil sea60W engine oil and 80w-140 gear lube in the Tranny, transfer case, and diff's. . .
it could be a replacement engine but i'm doubting it .