I purchased a Crown Graphic a couple of weeks ago with a Graflex Optar 135mm. The camera is in excellent plus condition but the lens slow speeds are way off. Today I won an auction for a Crown Graphic Special with a Schneider Xenar 135mm lens along with the flash, some bulbs and case. I don't think the camera is in as good condition as mine but I am hoping to swap lenses and would like to know if I have to swap the cams also. I watched a video on how to change the cams but would rather not have to if at all possible. Are all 135mm cams the same or are there slight variances that would throw the rangefinder off?

www.graflex.org aka the home page, Cameras, Graflex Graphic Model History, Pacemaker Speed Graphic or Pacemaker Crown Graphic, Interchangeable cams = http://www.graflex.org/speed-graphic/top-rangefinder-cams.html
4 cams for optical focal lengths from 132mm to 136.4mm.