Thanks Thewespaul and jwalterus
I spoke with the truck owner and learned some things.
It's an 1989 with a 94 engine.
The truck has just under 300,000 miles on it, no idea how many miles on the engine.
He's the second owner, previously owner did the engine swap and added a Garrett turbo.
He hasn't been using coolant additives, and doesn't think the 1st owner did.
Very little oil leakage.
Runs well.
Any deal breakers yet?
It may take a little time before I can look at it. The title is in his father's truck and his father went to Houston to help out.