[Dick Boneske]

Beginning in 1964 and through 1966 the end carb throttle plates have a .026" hole through them. I have asked this before, but still am not certain why engineers added this. I have been adding these holes on all Tri-Power end carb throttle plates for many years now.

My theory is that the small amount of airflow actually moves a tiny amount of fas from the end carb float bowls through the venturi cluster. This prevents the fuel in those carbs from developing sticky, varnishy deposits. This would be for drivers who seldom or never open the end carbs. The fuel in those carbs evaporates and leaves deposits in the float bowls.

Another possible reason for the holes may be to allow a very small amount of air flow into the intake manifold, exhausting any vapor and liquid fuel in the area above the throttle plates. If the vapor and liquid gas is not sucked into the intake, the liquid will seep into the intake and may affect hot starting.

Similarly, the gaskets between the throttle bases and the float bowl were modified to vent the area above the throttle plates to improve hot starting. This change was made in about 1963 to all three carbs.

Do any of you have theories on this?