| |
Click on image for the lowdown. 
====
| | | Forums66 Topics128,068 Posts1,055,882 Members48,428 | | Most Online14,466
Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down
with Ads!  Again, thanks!
| | 
#90535 09/04/2004 10:37 PM | Joined: Apr 2004 Posts: 31 Junior Member | | Junior Member Joined: Apr 2004 Posts: 31 | ...the speedometer...
Hey' bolters... finally got around to installing my new dash board into the '65 GMC... went for Autometer antique-looking guages... Volts read 14.3, temp reads 200 degrees, cooling fan on, 180 degrees off, oil pressure reads 25 to 40 psi depending on engine speed... Fuel guage I couldn't get to yet, but not concerned right now...
However... the speedometer reads nearly 15 mph off... Vehicle speeds is say 50 actual and indicated speed is, maybe 35... This I would like to correct somehow... I have no idea on how accurate the OEM was, it was trashed before I got it....
Any ideas?
Any help, as usual, greatly appreciated...
Thanks, Pete
Pete in NE PA
1964 Cheverolet Carryall
1965 GMC 1/2 ton
| | |
#90536 09/05/2004 3:44 AM | Joined: Jul 2003 Posts: 586 Shop Shark | | Shop Shark Joined: Jul 2003 Posts: 586 | I would guess and say it is probably your
rear tires. When the speedometer was made, it
was set for a certain diameter size tire.
You can check on the factory stock size and
compare it to what your running. Also, if you
changed you tranny or rearend, this will
affect the speed indication too. | | |
#90537 09/05/2004 1:20 PM | Joined: Jan 2001 Posts: 662 Shop Shark | | Shop Shark Joined: Jan 2001 Posts: 662 | | | |
#90538 09/08/2004 6:28 AM | Joined: Oct 2001 Posts: 3,458 Extreme Gabster | | Extreme Gabster Joined: Oct 2001 Posts: 3,458 | Most modern automotive speedometers indicate 60mph at 1000 rpm cable speed. You should be able to get an adapter from a speedometer shop or you can change your drive gear in the transmission.
Paint & Body Shop moderator
A lone amateur built the Ark. A large group of professionals built the Titanic. | | |
|
|
| |
