78 speedometers

[Hantke]

So my buddy has a 78 shortbed stepside C10 W/ a 350 V8 and a manual transmission, well, the dash was originally setup for an automatic so the speedometer doesn't work with the manual transmission in it now, so if I was going to fix the issue, would it require a new speedo cable and new speedometer? I haven't looked at it yet because he shipped out a while back, but being in fairly sound mechanical condition I think it would make a great little truck to play around with.

Would I be best replacing the speedometer and cable, or is there an adapter or something? Whenever I try looking it up I'm finding clusters for sale, but not the info I need.

Thanks!

[Titomars]

So what was changed the trans or the cluster?
If the cluster: the speedo heads are the same for all transmissions. Try making sure the cable is fully seated on the head. it will self lock when in correctly.
If the trans was changed: first make sure there are speedo gears in the trans and that they turn. Then check if the cable is connected and or reaches the speedo sleeve (port on trans).

[Hantke]

Originally Posted by Titomars

So what was changed the trans or the cluster?
If the cluster: the speedo heads are the same for all transmissions. Try making sure the cable is fully seated on the head. it will self lock when in correctly.
If the trans was changed: first make sure there are speedo gears in the trans and that they turn. Then check if the cable is connected and or reaches the speedo sleeve (port on trans).

I believe the transmission was changed, the cable now is seated on the speedo, but he said before he left it didn't fit on the transmission. I haven't got to look at the truck yet, but I can get it from him for $1000, so I'm debating on it.

Thanks!

[Titomars]

Originally Posted by Hantke

I believe the transmission was changed, the cable now is seated on the speedo, but he said before he left it didn't fit on the transmission. I haven't got to look at the truck yet, but I can get it from him for $1000, so I'm debating on it.

Thanks!

so the cable is too short. GM speedo cable ends are the same for all years that used them. So it has to physically thread on if it reached. You will probably need more than just a cable though. Odds are the gears will be wrong for the truck since chances are pretty slim the gear ratios were the same in both trucks.

[Hantke]

Originally Posted by Titomars

so the cable is too short. GM speedo cable ends are the same for all years that used them. So it has to physically thread on if it reached. You will probably need more than just a cable though. Odds are the gears will be wrong for the truck since chances are pretty slim the gear ratios were the same in both trucks.

Okay, that doesn't sound too horrible, is that an easy fix? it sounds pretty straight forward.
I am seriously thinking about making this into a nice little cruiser or something along those lines, but for now I just want to clean it up nice and work out any flaws so I have a nice reliable truck I can use to haul my tools around for work and cruise around the country side.

[Titomars]

Originally Posted by Hantke

Okay, that doesn't sound too horrible, is that an easy fix? it sounds pretty straight forward.
I am seriously thinking about making this into a nice little cruiser or something along those lines, but for now I just want to clean it up nice and work out any flaws so I have a nice reliable truck I can use to haul my tools around for work and cruise around the country side.

the cable is. Just figure how much too short and the I add 4 inches to that. So you measure from the end to where it needs to go. Say its 12 inches shy plus 4 equal 16 inches. Then pull the cable out measure its length overall casing end to casing end, not including the core. Say it is 88 inches then add 88 + 16 = 104 inches. That is what you need. If there is none that exact length you can fudge it a couple of inches either way. In the end you want nice gentle curves not sharp bends and loose plenty of give not pulled tight.

[Hantke]

Originally Posted by Titomars

the cable is. Just figure how much too short and the I add 4 inches to that. So you measure from the end to where it needs to go. Say its 12 inches shy plus 4 equal 16 inches. Then pull the cable out measure its length overall casing end to casing end, not including the core. Say it is 88 inches then add 88 + 16 = 104 inches. That is what you need. If there is none that exact length you can fudge it a couple of inches either way. In the end you want nice gentle curves not sharp bends and loose plenty of give not pulled tight.

Awesome, what about the gears?

[Titomars]

Originally Posted by Hantke

Awesome, what about the gears?

That is a little more complicated. first you need to get the speedo working.

[Hantke]

Originally Posted by Titomars

That is a little more complicated. first you need to get the speedo working.

Cool, thank you!