David Vizard - Which to prioritize - PORT FLOW or PORT VELOCITY?

273 said

Yes I know.



Ideally but obviously it ain't as sensitive as some make it out.


People bring velocity a lot especially warn about too little velocity never really hear warnings about too much though (which is a thing), but those that warn seem to have no idea what the right velocity or csa or port volume is but their sure you probably need smaller than your thinking of.

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As DV related in the video, Darren Morgan says velocity, velocity, and velocity. That said, a smaller volume head on a larger displacement head will have the flow stall at some point. Essentially what we see on a flow bench when the flow gets to a plateau or drops as the valve is lifted more.
Again it all comes down to the rest of the engine combination for port volume, flow and velocity.
As stated previously, the Ford Boss 302 engines had ports designed for TransAm racing. Those race engines ran up to 9000 and sometimes 9500 RPM. The 1969 street engines had the largest valves, and proved to be a bit soft at the bottom end. For 1970, Ford reduced the intake valves a bit, which helped street performance a little. Ford installed a rev limiter in the distributor to limit the RPM to 6500. The intake ports and solid lifter cam would let the engine rev freely to where the con rods would fail. The Boss rods were upgraded HiPo 289 rods, with stronger bolts and half moon machining for the bolt heads. Same length as the 289 at 5.155", but much heavier. Then there was the race rods that are visibly heavier to stand up to the 9000 RPM race conditions with occasional runs to 9500 RPM.
The Dodge/Plymouth 304 engines were destroked 340 engines and ran at 9500 RPM with occasional runs to 10,000 RPM.