Technically yes.

BUT...

1. Are the port threads and sizes the same
2. Is the hole for the push rod the same depth
3. There CAN be different porting on the inside that might give different braking characteristics, good or bad.

I would call Raybestos and ask them for a comprobable.

Unless the MC is a rust bucket inside a rebuild might be in order.

Looks like disk drum cores are in short supply.

 

If he can use a nice used OEM one from a '70 manual disc 340 Swinger then PM me.

 

I just put this one in my 72 Dart with front disc/manual. 15/16 bore makes for a little more pedal travel and better feel on the manual brakes. So far so good. All the specs are there on Summit's page.

Right Stuff Detailing DBMC15 Right Stuff Detailing Master Cylinders | Summit Racing

 

$300 is ridiculous. These MCs are widely available, and there is nothing special about a 1968. Just keep shopping.

 

i put the wilwood style in mine ajustable pushrod etc. Got it from mancini racing it wasnt 300 maybe half that 160 ish..