There is a 4 or 5 page thread on the Zone about it started by me. I am a teacher at a juvenile correctional facilty. That means my students are year round, ages 13-19, can get paroled or sent to prison at any time. I have had 8 different students working on it in the past year that it has been in my room. Everytime I get a student to where he can really start getting stuff done, he gets in a fight, transfered to prison or sent home. The hold up for the past month has been the welding class. They are installing new ventilated booths and have been pretty much shut down since Thanksgiving. I should be able to get a welder (machine and student) down in my room next week again. That will get the t-case mounts, seat frames and radiator mounts all finished up. We try to let the students do the work instead of just watching us do the work. Otherwise, it would be done already.
I never drove in the 4BT truck with Lee. However we all played at Land Between the Lakes park for a week in 2004 together. I was riding in a 350 powered K5 Blazer. Lee kept up on the roads and trails with the Blazer, Tom, Spicergear, and his Tall Deck 427 Rockwell axled M715 and several other 454 powered M715's just fine.
Lee also had air conditioning on his truck. He drove it daily in Baton Rouge for a year or two. He never had any complaints about around town driving. We talked for hours on the phone about how he was wearing his XL tires down driving on the road so much and if 35x12.5 BFG tires would be worth putting on for his daily driving. He decided against it due to lower top speed. He said the increased accelation wasn't needed.
The man Lee sold the truck to had it in a shop in TN a few years later. Kwai and I stopped in to pick up some other parts on one of our long range parts trips. The shop owner said the truck was amazing to drive around. Plenty of pep and good high speed manners. He never mentioned what he considers high speed.
The super smooth aerodynamic shape of the M715 really starts sucking power above 60 mph. My 396/NV4500 powered truck needs much more throttle to hold 65 than it does 60. 70 has the fuel gauge moving faster than the odometer. That is why I normally drive around 54-58. Wind noise is exponetially louder above 60 as well. Lee used to brag about how he could still hear his super pumped up sound system at 70 with the top off going down the interstate. My point is that he drove it that fast often. I am just not sure if he did any hours long highway speed runs.