[davidgto]

Doing a 65 GTO automatic to 4 speed conversion. Is there a speedo cable extension available so as to not replacing the entire cable?? If so, where would I find such an item. The automatic cable from factory is not long enough to go to the opposite side of the Muncie transmission.

[Skip Fix]

There is I used one in my 79 Camaro. I think I have a box at home with the part number.

[Lemans64]

Muncie trans in a Pontiac has the speedo output on drivers side. Yours has a Chevy tail housing.

[Rich-Tripower]

For no more than they cost, it seems like the simpler and probably most cost effective solution is to just get the correct length speedometer cable. If you do have a Chevy tail housing, you can just buy the equivalent cable for a Chevelle. Though if this is the case, you will need to run the cable differently as in a Chevelle. In an early Chevelle, the cable runs under the dash and goes through the floor just to the passenger side of the hump in the floor for the bellhousing. I can post up some Chevelle assembly manual pages if it would be helpful.

[Rich-Tripower]

If needed, here is a scan of the assembly manual page for a 65 Chevelle. If needed, this could be useful to the OPs purposes. I can look up the correct length of cable you'd need if you want to go this route.

[TB1]

I ordered a cable for a 65 Chevelle with a 4 speed cable exits in the stock location then I ran it up over the bellhousing and down to the passenger side, Not stock but it works for what I was doing and it's out of the way. Cable was cheap about $30 Canadian

[davidgto]

Fellows I appreciate all the input and I am considering all the options you have mentioned. Yep it is a Chevy version. I was told, in the early 70.s ,a short cable was available, to add length needed in different applications. Does anyone know where to inquire about such?

[Tom Vaught]

When I received my Nash Trans, it had the short cable and the connector to work with the Chevrolet style Speedo Insert for the transmission.

I will eventually come across those parts again.
I just have the Speedo Gear Housing (with the "O-Ring Seal" on the housing) but no trans driven gear or the proper
Chevy Speedo cable. Is 1965 and 1966-67 the same length?
Anyone know the Chevy driven gear for a 2.73 axle ratio?

Tom V.

[Rich-Tripower]

With a quick look up the same cable was used 64-68 4-speed Chevelles. 68 inches long.

Concerning the driven gear, there are so many variables given tire diameters,etc., I've always preferred to just drive it at a reading of 60 mph and measure the time over a mile, then having that figuring out the percent off and use that to determine the gear needed. A more modern way to do it is to down load a MPH GPS app on your phone, drive to 60mph on the app and then note the speed on the speedometer and determine the percent over or under driven and then chose the driven gear from there. You of course need to know which size of driven gear you already have in there to know now much change you need to choose the correct new gear.

I have a whole big calculator around here somewhere.....

[Rich-Tripower]

Here's a place to start: https://www.5speeds.com/calculators/SpeedoCalc.html

[davidgto]

Thanks, I will check into that site, Rich.

[60sstuff]

Hi David,

There seems to be some misinformation (more fake news) up above in an earlier post.

For a 1965 GTO, the factory Automatic transmission has the speedometer cable on the LH side.

My Original car is this design, just like the factory Shop Manual shows below.

Chris.

[Rich-Tripower]

I found an even better link, this is the one I was first thinking of. It tells you step by step how to go from what you have to what you need on the driven gear. You might want to view this ASAP and save a snapshot as the website is being redesigned and I'm sure useful pages like this will disappear in short order.

https://www.chevelles.com/shop/speedo.html

[burd]

Go to a Speedo shop, have them make up what you need.

[Skip Fix]

I'm going to the shop today will see if I can find box with #.

[Skip Fix]

I could not find that box, two other speedo cables. I went through the Pioneer catalog with a guy at Oreilly back then and looked at the descriptions is how we found the extension.

[davidgto]

Thanks Skip and all. Would like to put an extension on existing cable. Will try parts store.

[Bill Hanlon]

Google is your friend. Search for "speedometer cable extension". Lots of hits.

[Skip Fix]

My Camaro when it was a SBC TH350 and I swapped in a 383 and an ST-10 cable needed and extension so I went through that. I have a guy at OReillys that is in the "will call" for mechanics that looked through the Pioneer book and ordered a couple until we found a "male female" extension. I swore I kept the box for a referance but came up empty. When I swapped a Autometer speedo in I had to find one with a screw on at the speedo also.