A two-barrel integrated head was used in trucks from '75 to '84 . . . so my guess is that someone with a later truck ran into trouble on the bottom end - and swapped the short-block from a '73 to get back on the road . . .
I know there was a 250 integrated head with it's own valve cover in 1975 and 1976. And then there was the 250 integrated head I have in 1977 and 1978. Both of these are Monojet heads. In 1979 they went back to a non-integrated head for the last year of the inline six in Camaros, Novas, and Caprices. But I'm not sure what years the truck 250 used with the Varajet head? Was it introduced in 1979 and used until the truck 250 was retired after 1984? Or did trucks go back to a non-integrated Monojet head in 1978, and then changed to the Varajet in 1980?
