At full throttle the reversion problem is minimized, and the diff between big and small port is no big deal. The place a small port manifold excels is in throttle response and part throttle power. The small port 4 bbl manifold, makes my current 318 more fun to drive than any other 318 I've ever had. It has immediate throttle response w tons of torque, will spin a tire w ease at much less than full throttle. You can build engines like me your whole life before you find a combo like this. Ever put headers on an old Ford 360-390 ? same kind of deal amazing results for minimal effort.