So today I tackled the speedo cable on the 70 GS. My car is supposed to have a right angle adapter on the trans. Unfortunately, its long gone. And someone in the cars past tried re-calibrating the speedo by installing a two piece cable and an inline speedo reducer. It was still off by about 4 mph. I took Dave's (CopperheadGS1) advice and installed a one piece cable and the gray 22T gear. I looked up the speedo cable in my parts book. Its listed as- 1970 C.T. 4 speed with Rt angle adapter #6478175 cable and casing 57" long 1970 C.T. 4 speed without Rt angle adapter #6478178 cable and casing 70" long type CC370 Since Im not going to run the adapter, I started looking for the 6478178. So I google the number and see that Fusick has a repro of that number. They actually use the GM number as the part number. But its listed as 66" long. I figured 4" short might work. I order it, and when i get it, its an early style with a threaded speedo end. Odd. I call and they exchange it for thier number of 6478177 which has the quick disconnect speedo end the 70 takes. Still a 66" but the only other cables I found were 80" After the fact, I looked up the 6478177. It shows up in my parts book as 73 A body w/ T400 or 50-60 series big cars with T400s. GM lists it at 65.5" I installed it, and it fits nicely. The only issue is that I cant use both speedo cable clips that hold it in place as it passes under the bellhousing. I can only use one clip. Its fine. It fits nice and is well away from the downpipes and any other obstacles. But I'd like to get hte correct cable and be able to use both clips. Why they list the 6478178 as a 65-68 is puzzling as its clearly listed in the GM parts book as fitting a 70. Fusick lists the 6478177 as fitting 69-72 4 speed exc cruise control. Both are listed as 66" So.....who makes the corrct 70" cable??
Jason, i don't know if you are active on eBay but I bought a few speedo cables from motor city supercars. They seem to be able to cater to different length cables. I bought several because I couldn't find my clips during the resto and I have to route over the bell housing on my 71. The cable managed to contact the collectors and no more cable. I don't have the right angle adapter since I am running a lower rear gear. My cable is 80+" since it has to loop around in order to come straight into the speedo gear. They have a 442 four speed cable listed now that has the correct ends, but doesn't state the length. Sometimes oldsmobuick works.
Active? Im like a crack head on Ebay.:laugh: I just looked on the Ames Performance site and they list a 69" cable for a 70 GTO. Getting closer
Half the battle is finding the correct part. Now its bothering me that Im not using both clips! But I have to say that the new cable, despite being a little short, is great. my speedo needle is nice and smooth. The old cable must of had a bind in it and the needle was jumpy. I greased it too before I put it in with a little moly lube. Just for the record, in order to remove the speedo cable, the radio really has to come out. Once the radio is out, you can get behind the speedo through the radio opening pretty easily. If its an non A/C car, removing the radio is a pretty straighforward procedure. Comes right out through the opening. If its an A/C car, its a little more involved. The glove box liner, dash pad, upper A/C vent, and lower a/c ducting all needs to come out. its a tight fit with A/C. Thankfully the 70 is non A/C. On a side note- when I took out the plastic toe lick panel behind thats screwed to the firewall, it was cracked.....again! It cracks after the clutch pedal hits it enough times . its the second one I put in too:rant:. I have on left that minty mint. I guess I'll just save it. Maybe Im too enthusiastic with the 4 speed? :grin:
Jason, Sorry to hear about the to panel. I have not cracked mine yet. After working under the dash of my friends Olds today it just reinforces how much I hate AC cars.
After changing mine out for the third time I figured out a better way to get the cable out. First take off the small piece of panel directly under the steering column. Then take out the vent duct that runs across the bottom of the dash (on ac cars). Then drop the column by taking out the two nuts that hold the column up to the cowl. At this point you should be able to reach up behind the speedo and push the clip that holds the cable in. A bit of contortion will be required to pull the cable slightly at the same time. Until I figured this out I was taking the dash pad out and cluster, etc. just to get to that little release clip. Hope this helps.
