Abstract: An internal combustion engine recessed manifold entry reducing internal/external merge intake collector structure and working process for two and four-barrel carburetor and fuel-injection throttle-body throttles and manifolds. Normally located between the carburetor/throttle-body and the engine intake manifold, this device's design has recessed internal/external merged-bore passages that extend into the intake manifold entry area. Lowering the flow passages into the manifold plenum provides the opportunity to have their passages channel reverse runner flow away from the entry air throttles. This is accomplished by externally merging the multiple throttles' flow passages together so that they can be lowered to extend below the manifold mating flange surface. These changes allow more flow efficient performance tuning that deliver higher specific output power while making more efficient use of the air and fuel being consumed by the engine.