Nope, no serpentine. It's an '81 258 with Air Pump. I removed all the belts in that picture.
I have been looking for a speedometer solution for the two Eagles I'm currently working on. The first one is a TBI setup with a VSS that has 7/8" input and 7/8" output. The second is an MPI setup with a VSS that has 7/8" input and 5/8" output. For both of them I am using a transfer case speedometer gear and housing from a 1992 Jeep Cherokee. That housing is pictured in this first picture. It goes right into a stock Eagle transfer case or any of the "New Process" Jeep transfer cases.
For the TBI Eagle the speedometer cable is easy. I put the 92 XJ speedometer gear and housing into the Eagle transfer case which ends in 7/8x18 male ends, then put the 7/8 female to 7/8 male VSS on it, then purchase a common 7/8 female to 5/8 female speedometer cable to go up to the Eagle speedometer, which has 5/8x18 male threads on the back. A speedometer from a J10 or a CJ7 will work, so I ended up bying a CJ7 speedometer cable for about $20 from Rockauto.
On my Eagle I also added a 40" lower cable from a 1987 Monto Carlo which has 7/8" male threads on one end and 7/8" female threads on the other. That cable goes from the transfer case up to the inside of the vehicle so that the VSS will be better protected from the weather. My VSS is under the driver seat.
For the MPI Eagle it is more difficult. In the first picture above the cheapest VSS available is pictured. Companies like Hesco offer a VSS with 7/8 threads input and output, but those cost between $80 to $120 dollars. The Mopar part costs about $30 and is readily found in junkyards. It has 7/8" input threads and 5/8" output threads. The Mopar fuel injection kit actually comes with a fancy nut that has 5/8x18 threads in the inside and 7/8x18 threads on the outside. That is pictured. If I could find that nut for sale it would be an extremely easy conversion. I haven't found it yet although I did hear of one website that may have them if you contact them. In Tougeagle's Caroline car he used a hardward store nut to accomplish the same thing, but it didn't have the correct threads so he used pipe teflon to make it wedge tightly.
I just did an exhaustive search for a vehicle with 5/8x18 female threads at both ends of the speedometer. No such car exists. The closest I found was 88 to 93 Dodge Dakota cables. Those have 5/8" at the transfer case and a chysler snap on end at the speedometer. This would work if you use an Equus 9871 Adaptor. The cheapest price I found for the Equus is $25 from JC Whitney. Some other online sites had the same part for the same price, but JC Whitney is offering a free shipping promotion that makes them the cheapest right now.
Equus 9871 Adaptor:
Dodge Dakote Speedo Cable:
I'm tempted to buy the Equus adaptor and find a speedometer cable from a Dodge Dakota in the junkyard. That would give me a speedometer cable for my MPI Eagle for about $30. Alternatively I might just bite the cost and order a custom made cable. Two companies online offer to build me a custom cable with 5/8 female threads at both ends for about $60.