Ford Repair: 85 to 140 speedo., speedo cable, tranny

Question
I'm wanting to convert my 87 GT's 85 mph speedo to the 140. I've heard theirs a gear in the tranny to change out. Is this correct and is their anything else to do?  Thanks...Steve.

Answer
They have kits that change the gauges but they can be expensive.  If you get the kit with the speedo, you dont have to change any gear.  If you put a sticker on your speedo, you have to change the gear that is on the speedo cable, the gear is right where it connects to the transmission.  Im not sure what ratio you would need.