41' Dodge Coupe Speedometer cable

[41RogueCoupe]

I am trying to figure out what the thread size is for the speedometer and cable going from the trans to it on my 41' Dodge business coupe.

Mine is a special case, as my 41' business coupe sits on a 79' El Camino frame with a 71' El Camino 402 BBC in it. The car has a TH350 auto trans. I am trying to figure out how I can hook up the speedometer cable to the original 41' dodge coupe speedometer. 

I believe the 79' El Camino speedo cable connection to the speedometer is a 5/8-18 thread, so could I get an adapter to connect this cable to the 41' coupe speedo or something? Just not sure what size the thread connection is on the 41' coupe speedometer. Thanks

 

[Sniper]

Put an ATP Y803 in my 51 Plymouth, a bit long for my needs but probably fits yours as well.  This one is a 7/8-18 female (trans end) to 5/8-18 female (speedometer end).  Same one would work in my 65 Cuda as well so that was the common sizes for MoPars back then.  As for what a TH350 takes, dunno, I don't speak GM.

 

So I go to look at what a 79 El Camino takes and guess what?  ATP 803 is listed as fitting, lol.

[41RogueCoupe]

Thanks Sniper. So you think something like this part would work? 

It's pretty long at 83". The fittings it says, 7/8-18 female (that will fit the th350 trans) , 5/8-18 female - will that attach to my 41' dodge coupe speedometer fitting? 

appreciate it

[Sniper]

That is the exact on I used, not 100% sure a 41 Dodge has the same speedo connection as my 51 Plymouth, but I would roll the dice and get it, lol.

[41RogueCoupe]

Well, I tried the speedo cable Sniper recommended. It fit on the TH350 trans fitting, but didn't fit on the 41' Dodge Cope speedometer fitting

Does anyone know the size of the fitting on the speedometer for a 41' dodge business coupe?? Thanks

[41RogueCoupe]

I was able to find the fitting size for the 41' Dodge coupe speedometer, if it's helpful for others. 
5/8 -18 is the stock thread