Hi guys, I recently purchased a 1978 Z28 with a few modifications and a whole lot of gutting. Anyways, I want to hook up the speedometer again, and I don't know how to. The previous owner, put in a 406 stroker, and a 350 turbo tranny with a 3500 stahl. I honestly don't know how to hook it into the transmission or where the cable/ connector even is or what it looks like. Could someone please help me with this? Thank you. The rears are 4.11s if that matters?

 

well first things first the speedo cble runs from the spedometer to the firewall and through a small hole near the column and pops out under the car almost into the inner fenderwell then it will run to the drivers side tail shaft of the th350 about 2 inches from where the shaft housing bolts on.

second you need the gear calculator and a few measurements of your tire size Speedometer Gear Calculator and Charts - TCIŽ Auto
this one is pretty close to right the first try unless you have crazy gear set up in the th350

the best way to know what to look for is just go buy a new one they are two pice units and relatively cheap ~30 for both i think

 

I'd hook the speedo cable up to gauge and trans, and go for a drive. Have a buddy go ahead in a car and set his pace at a certain speed, then you can determine how far off you are now. Might be your TH350 has a correct setup, and wont need a new gear. Changing speedo gears is easy, but involves dropping the tailshaft off the TH350. No sense in doing that, until you're sure it's off.
I have a friend who uses his cell phone app. as a speedo. He has a windshield mount, and simply sets the phone to the MPH app, and it tells him his speed as he's traveling. Cheaper and easier than getting the car set up.

 

i am under the assumption that the car does not even have a cable in it at the moment. does it?

 

You are correct sir. My car was a drag car before I purchased it. So now it's my job to make it a daily driver.