Gus....try to stay with me on this one...I am about to start another fire storm in this thread....... There are many flywheels (salvage yards if you wish) that accomodate multiple pressure plate sizes. 12" is good. I run 11" because I look for total contact area. If the 12" is only 12 on the outside diameter and yet 11 in the inside, you have no more surface area than a little 9.5" or a decent 10". Think about how a Lenco setup uses 6-6.5 inch contact area. We need surface area way more than diameter sizes to stick the torque to the ground. Can you apply a 10 or 11 or 12 inch disc in the bell? yes the fly wheel doesn't grow, just mating area (machined surface) and the right ones will allow you to put in what you wish. Remember, Surface (Contact) area is what you want. Too many suppliers cut corners to save a nickel and you have a huge disc and no "meat" for application.