since a 7.3 idi and 6.5 mechanical are pretty close you could get a DB4 injection pump for a 6.5. its a marine version of the pump in my truck but flows more and its mechanical. fabricate a way to put it on there and get higher pop nozzles on the injectors. then top it off with head studs and a HX-35 turbo

 

6>8 dont ya know

 

Our two wheel class says no turbos but says nothing about diesel and there is 1 6.5 Chevy that does well against the small block Chevys. It isn't winning but the driver is having fun spending little getting close to the guys spending allot. Just my $.02

 

I took my F-250 6.9 diesel,extended cab long box 4X4 with 4.10 gears (manual trans )and entered it in a sled pull this fall. I pulled in 2nd low and never ran out of power just spun out.

One thing is the truck is light, 6400pounds with me in it!! plus it has a cattle guard in the front and a heavy spring loaded Ag hitch in the back. Could easily shave off another 250 pounds right their. Just think hang 1800 pounds of weights on the front end for the 8000 pound class

 

i have a 1984 with a hypermax turob and 6.9 i pulled it stock and it competed with the cummins and powerstrokes. i have done some mods to my pump since then and waiting for another pull to findout what it will do.