Slowest...... that's a list. 81 Chev 3 ton with a 366 5 and 2 with a 17' box loaded with wheat. Empty it was a turd, loaded it could hardly even move. Most absolute useless engine GM ever made, a big block that a 350 would run circles around and last longer doing it.
Otherwise most of the gutless junk highway rigs I drove back in the day( Mack's, Kenworth's, and good old 466 powered International's)...... PASS.
For a D.D. type, dying 1986 GMC 4X4 K1500 with a 6.2 diesel. That turd barely could make the speed limit and took hours to get to it.
And actually my first job had a shop truck that was funny. 81 GMC R10 with a 250 straight six and a Turbo 350. Somebody filled it up with diesel and really made it run awesome after that. It couldn't do 55 mph, period.
