Original Zenith (at previously posted) for a 228 CID is Zenith O-11147. Original Zenith for a 248 is O-11148. Both have been superceded by Zenith O-11475, which in turn was superceded by Zenith O-14475. O-14475 is a current part number, and readily available.

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