Holley primary metering block stamped 5271
 

The Holley carburetor is List-4053. The primary metering block is stamped 5271. Can anyone tell me the application for this primary metering block.

The 5271 was used on the pri side of 9188AAA, 3310P 3878261 EH, 3310-2S. The 4053 used a 5584 (4053P 3923289 later issue). Also 3828 was used 4053P 3923289 Possible later issue. I don't see where a 5271 was used on a 4053 ...