what Bore master cylinder

Johnny Dart said
Doesnt sound like you are staying stock look,so if I were you I would go to the light weight Mopar Alum mc.
This is the one I installed on my 65. You will need the 2 to 4 adapter for it.
This one is a 1 1/32" bore. Stops real nice. Got a new mc with adapter for $100.00.
Also used the stock push rod with it. Simple bolt on install.
Click to expand...

That's the 1.03" MC I mentioned that Doctor Diff can supply you with (including adapter). It will increase pedal effort from the 15/16" you have now - probably by quite a bit. That's what I run. So now, we've come full circle.