far as modern engines are concerned 90 percent of the time if you use the correct grade for your climate you will have years of good service. i would find brand a personal preference mostly.
78 to 80 i believe you could order a 5.7 before they decided it was a bad idea.
mine is a 1978 c10 auto. second engine , lucky for me its a gm goodwrench rebuild which was only used for about 5000 miles before it was parked.
more or less , im going to clean it up fix some dents and rust and stay pretty local (400kms from home more or less)
i plan to run the powertrain as is for as long as it goes.
all factory and brakes actually work. i dont trust them but they do work.
will be getting new everything master and down. along with tires and a complete tune up/oils
actually it is attached to the carpet in the green truck, there was no structural metal left in that thing. brown ford on the other hand is pretty ok. banged up badly but not that rusty