video on velocity and sound

[SpeierRacingHeads]

Is that Splash Zone in those ports?

Whatever it is, it looks to be far more "user friendly" than what I experienced when attempting to use Belzona 1111 to downsize some intake manifold runners.

Yes it’s splash zone with Devcon 2-ton clear epoxy over it.

[BradH]

Thanks. I'm going to give that a try and see if I can salvage the Belzona disaster.

Re port sound on bench: Even though a particular set of heads I used in the past performed well on the dyno and track, I remember clearly how they sounded like they were coming unglued on the flow bench at or above certain lift points.

Has your experience been that an improvement in flow stability, even at the cost of raw flow numbers, translates into a measurable performance improvement in dyno/track testing? I'm seeing heads of comparable MCSA/CSA and valve sizes that pull more peak CFM at higher lifts than some of my tests, but may flow less across much of the lift curve that matches the cam used. I don't know how much is an "it depends... " thing vs a general philosophy of port design.

[SpeierRacingHeads]

Thanks. I'm going to give that a try and see if I can salvage the Belzona disaster.

Re port sound on bench: Even though a particular set of heads I used in the past performed well on the dyno and track, I remember clearly how they sounded like they were coming unglued on the flow bench at or above certain lift points.

Has your experience been that an improvement in flow stability, even at the cost of raw flow numbers, translates into a measurable performance improvement in dyno/track testing? I'm seeing heads of comparable MCSA/CSA and valve sizes that pull more peak CFM at higher lifts than some of my tests, but may flow less across much of the lift curve that matches the cam used. I don't know how much is an "it depends... " thing vs a general philosophy of port design.

Always the clean, crisp port makes more power. You have some ports like a SB2.2 with the hole in the floor whistle if you don't fill it while testing. But for the most part, most of the exhaust ports while developing, are all sound related. I give numbers for computer programs, because guys still use them. Performance Trends has a program that is sound only. Hook a mic up to the computer and record the port. Find the best port, sound and performance wise, and use it as the master. Then compare. I have the beta version. Something can be learned.