original speedo with TH350/v8?

[vintage_car]

Will the original speedo from a 48' work with a TH350/350 v8? If it does, does it just use the stock speedo cable, or something else?

[mr48chev]

You might have to buy a universal cable and housing at the parts house that is a foot or so longer but the original speedometer will work ok. You will have to figure out how much it is off and change the speedometer drive gears though.

This site is one that a lot of us go to to help figure out what gears we need to change to.
http://www.transmissioncenter.net/sp...n_______va.htm
You can buy the gears at a local transmission shop or dealer though.
There is another link here
http://www.gtsparkplugs.com/SpeedoGearCalc.html
There are plenty of others on the net too.

What I've done lately is drive the rig down the road and use a gps to check the speed against what the speedometer reads and calculate the percentage of difference and the figure out what changes I need to make to the gears to correct it.

[OrrieG]

One of my 74 donor 4wd trucks had an extension cable because it runs off the transfer case not the auto transmission. Application would be a 74 K10 with 350/350th and 203 NP transmission. I have not had it hooked up yet but expect to have to change out the gear in the transfer case to get it calibrated right.