Quote "recently there was an NOS Zenith for the 1955 Hydramatic and the "Buy it now" was $500. Nope." End quote

This would be a really good price for a decent core. Dirt cheap for new old stock!

The larger Zeniths show up from time to time; just need to do your homework to determine which ones you can use.

Jon.

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop