1969 master cylinder
 

was there a change on the power disc camaro early vs later using the 346 and later using the 309 cylinder if so when did the change take place

http://www.camaros.org/suspen.shtml#Brakes

Per CRG: "Early 1969 disc brake cars also used the 5460346 master cylinder (for about a month or so of production) with later 69 cars using the 5468309 casting."

so on a 09D of 68 would have had the 54060346 master