Disc brake floating rotors
Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models
I extracted this information from Mike Tiberio and Charley Cole on the old Yahoo! Loopframe_Guzzi news group (which has now moved to Groups.io).
I got my [EBC] floater from a place called Vintage Brake. They were USD $230.00 each side. They had to order them from England. I only paid USD $15.00 shipping from their US location to my house...part number was MD668LS and MD668RS. LS=left side, RS=right side.
They are listed as being for a Laverda SFC 1000. However they are dimensionally equivalent to the 300 mm rotors fitted to early non-le mans tontis and disk brake eldos.
I got the rotors and carriers for my race bike out of England through Vintage Brake as well...also drop shipped. Vintage Brake rocks.
IMO, there have been three major advances in brake technology since the early 70s. One is narrowing the pad track, to reduce the variation in rotor temps from the inner diameter of the pad track to the outer, which caused lots of coned rotors on early disc brake bikes. Another advance was the change from gray iron (early cast iron) to extruded cast iron. Better friction coefficient and less prone to exploding when drilled. The last would be floating or semi-floating rotors, which allowed rotors to be slightly off center in any of the three planes. Floaters self center, so no longer heat up unevenly like the early fixed rotors did. That allowed rotors to be much lighter and thinner than early rotors and was the end of heavy one piece solid cast iron rotors. Some brakes had AL carriers before floaters were developed... (LM I and Converts were a couple of early examples)...afterward all rotors were separately mounted on aluminum carriers. Good for wheel rate ratios...right Mike!!! You're one of the few people I know who is concerned with wheel rates.
CAUTION: Do not put floaters on a bike with early calipers like FO8s, unless you are qualified to make serious modifications to the calipers. The pistons on FO8s cannot extend far enough out of the body of the caliper to come in contact with a 5 mm rotor and then safely retract once you have even a little wear on your brake pads. After very little use, they will extend, contact your rotor, not retract and lock your brakes.