Help ID master cylinder brake & clutch

The brake/ clutch master cylinder on my roadster leaks around the bore on the brake side. The pedal does not hold pressure. All this came about when I had to replace a leaking front brake hose and couldn't get the brakes bled.
I don't know the make of this item. I'm thinking it is for a '60-61 Chevy truck? The bore ID on both cylinders is approx. 1.125"
Please take a look and see if you can ID it. HELP!!!

 

yes, off of 60s era GMC and Chev pickups - amazingly (because of GM's configuration), the brake cylinder is closest to the driver's side fender, and the inside cylinder is for the clutch. You can remedy this by switching all the internals side for side. Ansen makes (or made) a nice hanging pedal ***embly for that cylinder (firewall mount).

 

yep Chevy PU early 60s.

 

Thanks guys!
Just needed to double check on the master cylinder. Didn't want to order the wrong one.
I hate changing them. Always end up making a mess.