[Phxamigo]

After replacing the stock enjine & automatic trans. with a 305 V8 & a 350AT my speedometer reads faster than I feel I am going . I have a 55GMC 1/2 ton stepside second series truck. I don't know where I should post this help question. Thanks for any & all responses.
Tucson Guy

 

[runn141]

you need to increase the number of teeth on the speedometer driven gear in your trans.

 

[solidaxel]

Take your truck over to TJ Speedometer over on 1st Ave at Blacklidge and he will calibrate it for you

 

[DOUBLEDICK]

There are a bunch of us with these old Chevy trucks.If you go to the hotrodders lounge there is a thread "55 to 59 chevy truck owners"I would enjoy seeing pictures of your truck and hearing all about it.I started this thread to have a place for guys with these trucks to share ideas and opinions about there trucks.It is a good place to ask questions about your truck.

 

[jimfulco]

http://novaresource.org/speedo.htm has the formula you need for speedo gearing. You'll need your rear axle ratio, and your rear tire diameter. There's a tire diameter calculator at http://tciauto.com/Products/TechInfo/speedo_gears.asp

 

[Phxamigo]

Thanks

Thanks to all of you for your response re: my speedometer question.
Since I lived in Cleve. Ohio for over 30 years I'd like to know where Pedro,OH is from Run 141. I will eventually checkout the site you suggested, Doubledick, & will send photos after I take a few. Thanks again to all of you.
Phxamigo from Tucson. :welcome:

 

[xntrik]

You need to increase the number of teeth on the end of the speedo cable, or DEcrease the number on the trans shaft. Cable is easier unless your problem is extreme.

I have never in 30 years had any police officer refuse to radar check my vehicles. Just stop and talk to them and ask. :thumbup:

Those "along the road" radar trailers with the big readout numbers that let you see how fast you are going are a good check also.

 

[runn141]

You need to increase the number of teeth on the end of the speedo cable, or DEcrease the number on the trans shaft. Cable is easier unless your problem is extreme.

I have never in 30 years had any police officer refuse to radar check my vehicles. Just stop and talk to them and ask. :thumbup:

Those "along the road" radar trailers with the big readout numbers that let you see how fast you are going are a good check also.

i already said that in post #2, and i dont think those police radars are all that accurate.

 

[Deuce]

After replacing the stock enjine & automatic trans. with a 305 V8 & a 350AT my speedometer reads faster than I feel I am going . I have a 55GMC 1/2 ton stepside second series truck. I don't know where I should post this help question. Thanks for any & all responses.
Tucson Guy

If you still have the original transmission ... look at the speedometer drive gears in it and duplicate the same ratio in you new transmission ...

9/22 9 on the big gear and 22 on the little gear is a 2.44 to 1
7/17 ... is the same ratio ... ( OK ... it is 2.423 )

So just do the same thing to your T-350 ...
make the ratio in the 350 ... the same ratio as was in the old transmission

This will work if you still have the same rear end and tires ...

 

[xntrik]

i

i dont think those police radars are all that accurate.

Really? Try to prove it in court.

If you were a Trooper you would know that....

The new bands don't bounce/ reflect,
and any angularity in reading means that the clocked vehicle is going FASTER than what the radar says.

Fact is, they are "dead on".

 

[runn141]

Really? Try to prove it in court.

If you were a Trooper you would know that....

The new bands don't bounce/ reflect,
and any angularity in reading means that the clocked vehicle is going FASTER than what the radar says.

Fact is, they are "dead on".

whatever you say

 

[xntrik]

whatever you say

It is not "what I say",

it what is fact.

It is almost impossible to beat a radar speeding ticket. All the old arguments are not valid. When a Trooper says in court, "I radared that car at X mph" it is all over but the paying.

 

[runn141]

It is not "what I say",

it what is fact.

It is almost impossible to beat a radar speeding ticket. All the old arguments are not valid. When a Trooper says in court, "I radared that car at X mph" it is all over but the paying.

not everybody on here is gonna believe everything they read