Pretty simple question...any thing I can do to make this thing role some coal when it's being lugged down?
Fuel screw, and I think you can tinker with some stuff on the IP. Just remember that black smoke = wasted fuel and lower MPGs.
There is some info over in the diesel technical section I'm sure. I know I see this question asked about once a month or so.
Clear exhaust does not mean low EGT.
I have a friend who on a good pull, with absolutely ZERO exhaust smoke, managed to top 1300F without a problem..
If you plan to tinker, you need an EGT gauge. You run the risk of going KA-BOOM if you get it too hot.
Is this a TD? If na, I don't really think you'll ever see crazy high EGTs.
Anyhow, remove your throttle linkage, rotate 1 or 2 splines CCW, then turn the fuel screw in until the power seems back to normal. You'll need to play with the idle screw to level things out, but it'll roll coal. You may notice the idle hanging a bit, but that's one of the side effects. You may as well shim the governor while you're at it.
I did this a while ago, but reversed it so the smoke went away. It got old quickly.