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Old 02-01-2015, 05:48 PM   #12
69l46vert
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Join Date: May 2007
Location: Buxton Maine
Posts: 137
Re: 1954 GMC 4WD Ideas

Quote:
Originally Posted by OrrieG View Post
4.10 might be a little steep unless you get tall tires. My 74 axles are 3.74 with auto trans. There are rpm calculators online that let you play with the variables; tranny ratio output (1.0 in this case), rearend ratio, tire height and rpm. you can input any three to find the 4th variable. Salt flat racers also add in frontage area, drag coefficient to determine horsepower to get certain speed. Not a big deal for the trucks, but been playing with it for my Chevelle make over.
Thanks OrrieG, I tried one of the calculators and 4.10's at 2000 rpm with 31" tires gives 45 mph so I see what you mean. Not great for highway speeds. I really don't think I want anything larger than 31's either. Rick
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