Hi I just purchased a 78 Datsun 620 3 days ago it is vin# EHL620316810 .Acording to the owners manual it is a cab and chassis. It has what appears to be a factory flatbed which is one reason i bought it so I can haul things with it. It has an L16 and a 5 speed transmission. It runs and drives great even with the small engine and has electronic ignition. the engine is not what the truck came with and when i bought it the PO disclosed the speedo didn't work. no big deal so i thought I'll fix the cable or whatever.the question(kicker) is that there is no hole in the casting near the back of the trans.to screw on the speedo cable it is blank!BTW i found the cable neatly draped over the crossmember after i traced it from in the cab (at least it wasn't dragging on the ground).After consulting my newly purchased(used copy) of clymers Datsun pickups 68-80 (thanks Tacoma Book!) to find the location of the receptacle for the cable further searching on the net led me to a post on 5 speed swaps in nico clubs which lead me to believe the transmission is not stock either! 280ZX non turbo possibly? I was told by an old datsun specialist on the phone i found to explain the situation to a nissan dealer for help in IDing the gearbox.Now my ? would be is it feasible to use a sensor system ,swap for a correct 5 speed or change the back of the transmission to accept a speedo cable. I'm leaning toward a swap at this point and if so what is the best box to use? Thanks and hello everyone!

Hey there. I have the same problem. I just put a 5 speed from a 1980 720 4x4 in my 1974 620. No hole for the speedo:( I found out that in 4x4 trucks the speedo cable connects to the transfer case, not the tranny. So the tranny has blank where the speedo connects. My guess is that your truck has a 4x4 tranny. I don't know if the part for the speedo can be installed in the tranny.