Copal 3 sizes ?

I have a 360mm Apo Ronar in Copal 3 and I was going to use the shutter to mount a 355 G-Claron (barrel) I also have. In trying to fit the two, I quickly realised that this Copal 3 is too small for the G-Claron! My other Copal 3s do fit the G-Claron perfectly as they have a larger opening.
And there I was, thinking Copal 3s all had the same opening! Wrong!

How many different sizes Copal 3s are there anyway? And, can the one I have be modified to accept the G-Claron?

Thanks

There are two different types of Copal 3 shutters, the 3 and the 3S. I believe the 3S has a 56mm opening and the 3 has a 58mm. The 3S is a thinner shutter for situations where the front an rear cells need to be closer together. The complete set of specs for all the Copal shutters is on the SK Grimes web site.