40 pickup stock

Walt Dupont--Me.

Walt Dupont--Me.

Well-known member
Mathematician. Boy, is that a long word. A friend has a 41 pickup, all stock. 3 speed trans. 16in tires. He just installed 3.54 gears, The question for that big math word. What RPM should that stock engine be turning at 60 MPH? I know some of you guy can figure it out. Thanks Walt
 
The number I found on line for the tire dia is 28.8". If that is right, the engine would be at 2480 rpm at 60 mph.
 
Will your bud need to recalibrate his speedometer after changing gears (guessing from 4:11?), if he stays with the stock size tires?
 
Thanks guys. My friend came today and we hooked up a tack and it was running close to 2500 rpm at 60mph. He just bought the truck and was disapointed with the 4-11 gears. It was more fun to drive today. He did get the speed ometer gear and it's right on. Thanks guys. Walt
 
I swapped out the 4:11's in my panel with 3:54's and what a difference that made on the highway. Can be an issue if you are going up hills though.
 
If you change the rear gears to 3:54 you should also swap the transmission cluster and main shaft to 29/15. You do not have too but this will help with starting from a dead stop and will be easier on your clutch.
 
Walt Dupont--Me. said:
Thanks guys. My friend came today and we hooked up a tack and it was running close to 2500 rpm at 60mph. He just bought the truck and was disapointed with the 4-11 gears. It was more fun to drive today. He did get the speed ometer gear and it's right on. Thanks guys. Walt
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Walt is it 6 volt? How did you hook up a tach? I was told that a tach on my 6 volt 39 was not possible. With stock ballast resistor / skip coil.

Thanks Andy
 
Walt, you tell Ken I will be up and we can see who gets to Ainslies first from your dooryard, I'm bet'n on my 3:54's:D. Scott
 
adileo said:
Walt is it 6 volt? How did you hook up a tach? I was told that a tach on my 6 volt 39 was not possible. With stock ballast resistor / skip coil.

Thanks Andy
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You can always get one of those cheap digital ones that wrap around a spark plug wire. I have for my motorcycle. It works off a watch battery. Amazon sells them for about $15. Hide it in a spot that only you can see. Bonus is when the motor isn't running, it's a Hobbs meter as well.
 
Back in the late sixties, I put a tach on my '53 Customline Coupe, the only change necessary was the bulb to 6V and it seemed reasonably accurate as I recall. Tough to get it over 4000, but it sounded good trying.
 
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