360 sb. 2bbl iron intake or 4bbl iron intake with 4bbl to 2bbl flat plate adapter, which flows the best? thank you for your time. RR

Yup, one of these:
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They came on '88-'92 roller block 360 truck motors. Just make a block off plate for the EGR boss, and redrill the carb pad.
The only advantage for a 4 bbl. manifold over this one is weight savings if they let you run an aftermarket aluminum manifold.