I checked my 270 WA G-Claron on a Copal 3 shutter. The threads seem to match, but I can’t screw the cells into the shutter deep enough to match the cell spacing on the factory 270. Perhaps the shutter area around the threads could be machined wider to allow the larger diameter lens cells, or maybe the cell bodies could be machined down. It only lacks about 5mm (rough meas.) to get the right cell spacing. This test was with a newer Copal 3 that came on a Nikon 450M.