I am new to the forum, I am 18 years old, and I own a 1974 GMC C1500 Custom. It has a 250 Straight 6, 3 on the tree, and has at least 239,000 miles on it (the odometer indicates 39,000, and the original owner already put 140,000 on it by 1979).
The engine seems to have never been rebuilt, that...