I see the original D-Zus come up for sale on ebay every now and then. I'll bet some of the vendors may stock them too. Start with Wilkinson. Chuck Melton seems to have one of everything in his garage.
The exact oem D-Zus is no longer made, but there are some nice new D-Zus style fasteners available. Check out a race equipment supplier like Pegasus.
I still fasten my tub in place, I still have ALL of the original fasteners.
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