We had an intake like this on a 4.2L GM Atlas naturally aspirated for Bonneville racing. Air flow was not equal cylinder to cylinder resulting in varying AFR readings cyl by cyl. We had 6 O2 sensors and sequential injector control with Megasquirt 3. We then had a GM engineer offer to do computer flow analysis and make recommendations. He had us turn the TB 90 degrees with the blade opening clockwise viewed from above and we made a wedge spacer plate to angle the TB towards #1 cyl. This helped but did not fully cure the issue. I would lean more to the original Ford top manifold with the divided plenum. They made it that way for a reason.
As for TB size, I wouldn't go any or much bigger than stock as the turbo will push more air through anyway. The bigger the throttle body the less sensitive it is to low opening for normal driving and the less sensitive the TPS.
Bonneville car with 4.2L Atlas 6
As for TB size, I wouldn't go any or much bigger than stock as the turbo will push more air through anyway. The bigger the throttle body the less sensitive it is to low opening for normal driving and the less sensitive the TPS.
Bonneville car with 4.2L Atlas 6
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