I have asked those involved at Callaway who built the engine and it all comes back to a Callaway Cars engine being, "the one"
Reeves was quoted as saying so in an interview and later, John Lingenfelter's rebuttal did nothing to correct that if needed... Interestingly enough, the foggy rebuttal now serves as JL's final word onthe mater, as posted on the LPE website
I found this quote by "turboboy" who worked at Callaway Cars during the era.
JL did indeed build the motor in the Sledgehammer.....but do you know the rest of the story???? When we got the engine back to Callaway, it was dynoed extensevly, and REBUILT using our specs. The dyno book on that engine was as thick as a phone book. Trust me when tell you that it was not the same motor as recieved from JL when it finaly went into the car.
Here are the Tom Benford interview quotes from Vette:
...and the follow-up interview:T: Will Lingenfelter Performance Engineering be providing engines for the Callaway C5s as they did for the Sledgehammer’s historic 254+ m.p.h. run?
R: You know, I don’t know where that rumor came from. Perhaps now is the time to correct it and put the whole issue to rest. We contracted Lingenfelter to build a couple of short blocks to save us some time, which we turbocharged, but they didn’t survive our dyno testing, so they were never used in the Sledgehammer. That record was set with a Callaway-built engine, although John (Lingenfelter) drove the car to set the record, since we had a very busy schedule in Europe creating Aston Martin’s Group C effort at that time. So it’s appropriate to congratulate Callaway for building the car, and John Lingenfelter for driving it to its record speed. That’s the way it was.
T: Your corporate website states that Lingenfelter Performance Engineering built the 1,200 HP engine that powered the Callaway Sledgehammer, but Reeves Callaway said your engine wasn’t the one used in the car on its over-254 mph run. Would you care to provide a rebuttal?
J: Well, the only thing I’d say is that the people that were there and the people that were involved know the real answers and what the truth is. That will suffice for me.