I looked up the information, and Bill Heath was running a twin-turbo 6.2L with 16.7:1 compression, a Bosch in-line fuel injection pump from a 9.0L Navistar V8 diesel (medium duty engine), intercooling via water injection, a TH400 tranny, and a 3.70 Ford rearend. This was all mounted in a 1976 GMC shortbed.
This truck ran the 1/4 mile in 11.42 seconds at 116.34 mph. The engine was dynoed at 582 hp at 4700 rpm, and 786 lb-ft of torque at 2650. Max. rpm was not governed but kept around 5100 rpm by the driver.
Bill later added nitrous and produced even more power, but on one run testing this system out, the rear end let go and the 6.2L went to the moon, running so fast that it bent all the valves, pushrods, and other valve train components. The tach recall showed 8460 rpm when it grenaded.
Sadly, the engine was stolen while it was torn apart, and he never built another one.
This information was taken from an article that Bill Heath wrote on the Diesel Page in 2001.