Thanks for the adivice.
I did have the throttle wide open (using the throttle knob in the cab, which I know is working), so my numbers are as good as they are going to get.
I don't know when/if the engine has ever been overhauled. It has about 48K original miles on it -- or at least that is what the odometer says. Judging from the manifold bolts, I'm not sure it has ever been rebuilt. Those bolts look like they haven't moved since the truck was built.
Well thanks for the info guys. I'll just keep driving it until it clearly needs help -- like big smoke clouds or something!
