So I started with an original paint truck with a healthy small block and got talked into building and dropping in a 6.5, my first diesel, because it would be easy and economical. almost 2 years later I just started driving this truck. Great power terrible economy. Granted the truck is a 3/4 ton with a th400 and 3.55 posi. My biggest mods are arp head studs, some head port work, bottom end girdle, 3" piped intercooler (32x18x3), bosch marine injector nozzles and tips on stock injectors (they all pop tested at 1900 psi after rebuild), stock injection pump turned up to the max. 3" exhaust with a high flow muffler. I have a turbo master on it but I still need to put a boost gauge on the engine. I'm hoping that I have the turbo master currently set to keep the turbo (stock unit) in one piece while I wait for the boost gauge. I've only got 550 miles on the drive trane so I'm keepin my foot out of it. So far I'm looking at 10mpg around town and 13mpg hiway. My timing is set at 4 degrees right now. Thats where I stand. I've read in multiple places not to push this turbo past 13-14 psi. So I still have some tuning to do and what not. Here is a link to my full build of this truck 67 gmc (http://www.67-72chevytrucks.com/vboard/showthread.php?t=290922)

Looking good. Keep us updated.

So I have almost 3000 miles on this and I've had a few hic-ups. Nothing major just learning curve stuff. I've towed about 5 3/4 ton trucks home to part out with this one now and with a single car trailer and 5k lb truck on it, it pulls really well. So far I do have a little bit of an oil consumption issue but I've identified a couple leaks to take care of. Fuel econ. is still less than spectacular at 14ish on the hwy, and 10-11 around town and towing.

You have a great truck! Maby put a 4L80e in the truck or an overdrive behind the TH400. What are your rpm`s @60 mph? Smaller precups are also good for fuel econ.