If this thing is about 1 1/2 " long and has a short removable "Stem" then it is the sound dampener.

Tom

What?

Sorry I was talking about at the dash between the head and the cable, it is a Ford-O-Matic

Trans.

By "Speedo can do you mean the Speed o meter head? If so and you have a T-85 Borg trans it could very well be the sound dampenter to cut down tranny noise thru the speedo head. This was standard on '57 Birds with the T-85 trans and possibly fairlane also.

312T85Bird

What?

My 57 Fairlane has an adaptor at the end of the cable that goes into the speed-o can anyone tell me why?

Thank You