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budman k20 · 11-18-2013, 06:36 PM

Jocko,

It is true that a SM465,Turbo 350 and 400's have a 1:1 final drive ratio but the automatics don't have lock up TC's so that is why they have higher rpms at a given speed. My truck rpm is a little higher at 70 mph due to the TC having a higher than stock stall speed.

11-18-2013, 06:36 PM	#11
budman k20 1972 K20 Join Date: Apr 2008 Location: Greenfield MN Posts: 360	Re: 4.11 gears and 287/75/16 Jocko, It is true that a SM465,Turbo 350 and 400's have a 1:1 final drive ratio but the automatics don't have lock up TC's so that is why they have higher rpms at a given speed. My truck rpm is a little higher at 70 mph due to the TC having a higher than stock stall speed.