I’m rebuilding a Street Avenger that my nephew has on a newly acquired car he just bought. I noticed on disassembly, that neither metering blocks had the vent whistles, and neither of them had been drilled for the retaining pin. Is Holley no longer using the whistles or is this carb using something different, or just missing them? I’ve never ran across this before. Carb# 80670-2, 2837