Hello, when I got my monte the speedo cable was hooked up but the speedo didn't work. I was told it probably doesn't have the right speedo gears in it. I have a TH400 in my 1970 which originally had a PG but previous owner before him had a TH350 in it. I have 3.73's in the car, which gears do I need to get my speedo to work again? Thanks!