I don't think there is a parts store 15/16 master cylinder that you can buy that works correctly. That is why Doctor Diff has them. He did the leg work to find a vendor who would build a 15/16 master cylinder with the correct reservoir and pushrod retaining feature and stuff like that. Mopar Performance used to have them made then they got out of the business. Eberg had them made for some time and now I think Doctor Diff is the only source.

Ahhhh, not a volume (or lack thereof) driven premium and no wonder I've had such a hard time locating one. Funny how it doesn't seem pricey now.

Thanks Andy

You can probably find something that works from Strange or Wilwood but typically those vendors don't care about the pushrod retention feature. Check ebay to see if Rick Ehrenberg is still selling master cylinders. I think he stopped selling them but I'm not positive. I think Mancini Racing only has the big bore size.

Still available if you want to go four bolt.

Thanks Supercuda, I want to stay with AL as part of my incremental weight control plan. Bragging a bit here, but so far, I'm about -30lb in lighter parts (measured weighing take-offs against replacements), mostly owing to A/C modernization. My added a P/S cooler, trans cooler, oil catch can and a relay box under the hood, along with my fast ratio pitman, C body size tie rods (AL sleeves), gusseted/reinforced K and LCA's take the net to -10 or so.

Andy, I'll check with Ehrenberg. I've pondered the big name aftermarket offerings, but cost/benefit takes me back to the Dr. Diff option, which I now regard as a bargain.