Speedometer cable location?
- Thread starter Rattee
- Start date
I ran a cable from the trans under the body and up through the floor board just behind the firewall and hid it under the carpet that goes up the firewall. I have a cable setup in two cars, it works, but depending on tire size, gear ratio and whatever I have forgotten you may have to change the transmission speedometer drive gear and the cable driven gear. None of this is hard but maybe time consuming. GPS units are probably much simpler. I have no experience with them so I don't know how accurate they are. In reality you don't really need a speedo, the nice policeman will tell you how fast you were going.
Indycars
Well-Known Member
I have a GPS spedo from Speedhut, but you could also use the tach once you get into high ghear.
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Made in Utah and the electronics has a life time warranty and 5 years on the rest.
Gauges: Universal-Fit, Custom and High-Performance | SPEEDHUT®
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I did those more than 10 years ago, and can't remember the length. Actually I might not remember if it had been last week. Nevertheless, one idea is to run a piece of wire along the path you wish to take and then pull the wire out and measure its length.
fletcherson
Well-Known Member
Just a FYI, I looked into their gauges when shopping for mine and yes, they are assembled in USA, but the components are not manufactured here, not all of them anyways. I’m sure they are fine but at the price point, I was less than enchanted by this fact. Sadly, in our global economy, few things are actually manufactured here anymore.I have a GPS spedo from Speedhut, but you could also use the tach once you get into high ghear.
Made in Utah and the electronics has a life time warranty and 5 years on the rest.Gauges: Universal-Fit, Custom and High-Performance | SPEEDHUT®
The Ultimate Aftermarket Automotive Gauges For Any Vehicle. Shop our huge selection of high-performance and customizable gauges - backed by a Lifetime Warranty!
fletcherson
Well-Known Member
You can get universal cables that you cut to length.
Looks like we didn't directly answer your question, except for 409T. I tried using the cable for my TH 350, and ran it thru the top of the transmission hump and back to the cable entry port. Gearing was wrong and I drove for awhile with an RPM/MPH conversion chart taped to the dash. Finally went the GPS route and am a happy camper. Works flawlessly and gives me the correct speed reading at all RPMs.
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AltBantam
Active Member
It's been nearly 6 weeks since the last post was added, but just in case someone is interested.... If you go with a mechanical speedometer, with a cable, you will need to calculate the correct speedometer gear to use. Otherwise you end up doing what Spanky did. The correct gear for the speedometer will depend on rear end gear ratio and tire height. For example, if your TH350 came out of a GM car with a 3.08 rear end and a 26" tall tire, then you use a new 4.11 rear end with a 30" tire, your speedometer is not going to read correctly. Luckily, there are calculating programs online to fix that. Originally, I was going to use a Buick 400 transmission with a pitch-switch torque converter. I used an online transmission speedometer gear calculator to determine the correct GM color speedometer gear to use. I changed my mind later and went with a more period correct manual transmission for my project. So that gear would not work, if I had bought it.
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