In the most recent high speed drive, Ole Bessie with 415,000 miles, 305 tbi, TH400, and 3.08 gear, fitted with 235/75R15 tires was able to sustain 78mph on I-16 in middle Georgia. She had 3 engines, 2 engine stands, and 4 tires in the bed! Oh, she was on a trailer behind a 26 foot Uhaul truck...