best cylinder head

I did a little research on this.

Annular booster: multi port fuel distribution more restrictive to air flow. air speed increased , the fuel atomization efficiency tends to increase, but at the cost of some over all flow restriction

Strait booster: Less restrictive to air flow but single fuel distribution point limiting atomization

Annular boosters usually generate a higher vacuum signal strength from increased air velocity due to their being more restrictive than the down leg boosters, in an identical throttle bore size, allowing the use of larger carburetors and/or larger cams while still retaining good metering stability. This promotes better throttle response, fuel economy, and much better mixture distribution, especially at lower engine speeds.

Strait boosters work well at wide open throttle on larger displacement car engines at higher rpms