19 inches. Be sure to put stiffiner rails on it for best results.
This is something that I have always wondered too. Duane, is the 19" a length you've found to be a good all around fit for most boats. The reason I ask is I don't full understand how a ride plate works and wondered if there was a way to determine the exact lenght a particular setup needs.
Just like the old school way of testing collector length using a crayon, can the burn on the bottom of a ride plate be used to fine tune the length?