RPM at 55mph

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Longgone

Longgone

John/68 Barracuda & Dart
Joined
Jul 12, 2005
Messages
6,896
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Location
Newport News, Virginia
How many rpm are you guys running at 55mph? I`ve got a bb/4spd/3.91 and I`m at 3000. I want to make this car more street friendly and I removed a 4.56/spool and installed the 3.91 posi. It still seems like I`m winding too high for around the city/highway.
 
What you need is a very tall tire,28-30 inch tall to reduce the rpm,s.What is the diameter of the tire you are running.What rpm would you like to run at 55mph.Any time you repalce the final drive you ned to repalce the speedo gear to reset the speedo with the right amount of teeth to give the right speedo reading.Some reseting can be done by looking at the speedo gear housing and turning it to the proper location on the housing,once the gear is installed.Look in the shop manual you will see four settings for a speedo gear housing and gear ratio.If you have 3.91 gears and a 28 inch tire you are going 55mph at 2600rpm.So now you tell us the tire diameter,if you have a tire smaller than a 28 ,the rpm will increase,if taller,the rpm will be lower,and you will ned to get the right speedo gear to correct the speedo,Mrmopartech
 
I've got a 727 with 4:30's and I run about 3000 rpm @ 55mph. I only see street duty cruising once a week, and the track every other weekend maybe. Never see the highway. But I have the lower gears to keep up with you four speeders.
 
Most people don't like my set-up, I have 3.23's with 28" tires; we drive fast on the highway around here. I'm going 85mph at 3000rpms all day long, very comfortably. Don't go 55 that much. Peace.
 
i am running about 3000rpm at 55mph to its ok with a smallblock that dont have the torque your bigblock should make
 
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