HELP! Tach identification

picked up this tach and for the life of me i cannot ID it, done all the searches here and the net, figured i would ask the experts - Thanks , Ross
By dodgord at 2012-01-16
By dodgord at 2012-01-16

 

not an expert....can I guess....maybe....a....boat?

 

Possibly a Studebaker? I believe they used SW gauges in their production cars during the mid'50's.

 

Sw greenline, weird hookup and pointer though,

Probably boat, but could be yenko, copo, and i didnt some fords have them too?

 

i thought boat maybe,that knob in the middle on the back adjusts to 8 different positions