Speedo recalibration

[Lonzoman]

Hello all...
Not that it is a huge deal, but today is my 50th birthday, and I've said for years that I want a truck as old as me (1964). Yesterday, for my birthday, I bought a 64 C10 stepside. She's a bit rusty and rickety, but I love it.

One of the many things I noticed was that when going 55 mph, the speedo reads about 80. The truck originally had the straight 6 / 3 speed, but have been replaced by a 1988 350 truck engine and auto transmission.

Is there a conversion tool or adapter for this upgrade, or do I need to have someone recal the speedo, or...?

Thanks! Love this new 'ol truck!

 

[Rich 5150 69]

Lonzoman, you can do this two differant ways, calculate the gears that you need and install into trans, or have it done or buy one of the speedo adapters.
lots of reading..

http://700r4.com/speedoCalc/speedocalc.shtml
http://www.tciauto.com/tc/speedometer-gear-calculator/
http://www.tciauto.com/tc/transmission-accessories/speedometer-gearshtml/
http://www.speedometershop.com/ratio.html

Ratio adapters, I`ve never used one but a lot of people have...
http://www.google.com/search?client...dometer+ratio+adapter&revid=2128935037&rls=en

 

[vwnate1]

Happy birthday !

Enjoy your truck .

 

[Lakeroadster]

Welcome to the forums! We need more 60-66 folks here. How about posting some photo's of your truck?

The 4th way is to use a GPS... 50 mph vs 80 mph... I've never seen or heard of a spedo being off by that much. It it an overdrive transmission? And perhaps the previous owner also changed the rear axle ratio too?

Lonzoman, you can do this two differant ways, calculate the gears that you need and install into trans, or have it done or buy one of the speedo adapters.

I think that's 3 different ways using two different methods.... technically speaking

 

[Rich 5150 69]

Mine is off by 20 MPH, when I decide to which way I`m going with the trans I`ll correct..or change rear gears...nah I like the quick launch....!

 

[Lonzoman]

Mine is off by 20 MPH, when I decide to which way I`m going with the trans I`ll correct..or change rear gears...nah I like the quick launch....!

Thanks Rich... I might look at it for a bit - I've got more important repairs at the moment.

 

[Lonzoman]

Welcome to the forums! We need more 60-66 folks here. How about posting some photo's of your truck?

The 4th way is to use a GPS... 50 mph vs 80 mph... I've never seen or heard of a spedo being off by that much. It it an overdrive transmission? And perhaps the previous owner also changed the rear axle ratio too?



I think that's 3 different ways using two different methods.... technically speaking

Yes, it is an OD trans... engine and trans from an 88 C/K truck. As far as the previous owner knows the rear end wasn't modified. Thanks!

 

[Lonzoman]

Enjoy your truck .

Thanks Nate - it is a sweet 'ol thing!

 

[Lonzoman]

Lonzoman, you can do this two differant ways, calculate the gears that you need and install into trans, or have it done or buy one of the speedo adapters.
lots of reading..

http://700r4.com/speedoCalc/speedocalc.shtml
http://www.tciauto.com/tc/speedometer-gear-calculator/
http://www.tciauto.com/tc/transmission-accessories/speedometer-gearshtml/
http://www.speedometershop.com/ratio.html

Ratio adapters, I`ve never used one but a lot of people have...
http://www.google.com/search?client...dometer+ratio+adapter&revid=2128935037&rls=en

I will look into all this, thanks so much for the help!