Speedometers and Tach's
Out of 10 cars unless someone went to the old charts that Ford had to compute the speedometer gears, 9 are incorrect. I had Dan Williams compute mine, tire size, gear ratio, ect. It's correct, there are many, many combinations of the right gear that goes on the tailshaft inside the toploader and the cable gear. All are color coded. The tachometers I have seen are off as much as 500 to 600 RPM so don't count on what you see as a true indication. The computed rpms and speeds are in the ball park, the others are not. True speed could easily be provided and checked with a GPS, they don't lie.
As for the gear, FE motors don't like to lug around under 2,000 RPM, and depending on the stroke, 390, 428, and 427 some even like 2400/2500 and up. My 427 being one that likes 2400 and up, I am considering a change from the 3:31 to a 3:54. For my driving, no Interstates, back roads, and no trips, the 3:31 is a little on the tall side. I coulnt even start ot think about a 3:08.
Rick
427 S/C , 427 Side-oiler, 4 Speed Close Ratio Top Loader, 3:73 Gear
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