Re: tach 20 pole
ooooh! That's a tough one. I had one that I acquired by accident but it was sold with the boat into which I put it.
You would need to look around boat yards, ebay, or Craigs list and even then, the used tach would be questionable. Find out if Brunswick is still the current manufacturer of Bayliner and contact them--but undoubtably that's going to be expensive. Coupled with the fact that the hole in the dash is so much larger, if possible you are better off removing the speedo and buying a matching set. Cover the existing holes with aluminum plate or nice looking wood, and re-drill the cut-out holes.