Max fuel economy?

[More Power]

I owned a 1982 "C" 6.2L diesel that I had rebuilt. The largest valves came a couple model years after the introduction of the 6.2 in an effort to improve power. GM abandoned the large valve heads because of a much higher likelyhood to crack. I've seen a couple sets of large valve heads, and I sure wouldn't use them. I'd leave the compression ratio at factory specs. The head gaskets are the concern here with higher CR, plus I don't think you could raise CR much because the 21.3:1 piston protrusion through the cylinder head deck is already taking up all of the room.

I like the idea of a DB4....

To get max fuel economy, think low vehicle weight, minimize drag force, maximize engine efficiency and drive at efficient vehicle speeds with appropriate gearing. Got to stay below 65-mph. With a light vehicle, slower speeds and correct gearing, a non-turbo 6.2/6.5 built as was mentioned above would get you the very best fuel economy.

MP