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| | | | Joined: Jul 2012 Posts: 26 New Guy | | New Guy Joined: Jul 2012 Posts: 26 | The PO of my 53 didn't choose to get the speedo functioning, so he added a tach to judge his speed. I b'lieve it has a standard rear end (4:11?)and everything, so how many RPM is 55 MPH?
THANKS in advance for any help!
Nifty'53 | | | | | Joined: May 2006 Posts: 8,351 'Bolter | | 'Bolter Joined: May 2006 Posts: 8,351 | In order to get an accurate answer, you'll also need to have the tire diameter. Once you have the tire diameter, final drive ratio, and rpm, you can plug them in here to get the mph you would be running at a given rpm. I used this to make a chart of common speeds and what rpm they are, as I have changed several items in the drivetrain that have altered the speedo reading.
Bill Burmeister
| | | | | Joined: Jun 2009 Posts: 2,201 Shop Shark | | Shop Shark Joined: Jun 2009 Posts: 2,201 | Just pick up a cheap GPS unit. You should be able to get one for around $35. | | | | | Joined: Jun 2009 Posts: 1,596 'Bolter | | 'Bolter Joined: Jun 2009 Posts: 1,596 | Just pick up a cheap GPS unit. You should be able to get one for around $35. Agreed. Many people use GPS as the speedometer in their vintage car either because the speedometer doesn't work, or because it's out. | | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | Mile markers give 60 seconds for 60 MPH, get out your stopwatch, low tech.
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Feb 2012 Posts: 60 'Bolter | | 'Bolter Joined: Feb 2012 Posts: 60 | Get your Android phone, download "Speedview" app, turn on GPS. Have a friend hold the phone while you compare against your tach.
Last edited by malibu67; 07/26/2012 6:17 PM.
1967 Chevelle Malibu (2nd owner)
1951 Chevy 3100
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