470 going to the dyno - HP/TQ estimates

I hesitate to even bring this up, since it usually turns into a pi$$ing contest……

The whole flow sheet is completely suspect…….because of the flow rate listed at .100 lift.
This isn’t me being butt hurt because the numbers are so much better that what I get……..it’s because the flow number is “impossible”………and not by a little bit either.
The airflow through a head at 28” of test pressure will only yield so many cfm per sq/in of area.
That number is 149cfm per sq/in.

The curtain area created by a 2.19 valve lifted .100” is .688 sq/in.
149 x .688 = 102.5cfm.

The sheet shows 150cfm.
Can’t happen…….it’s a fantasy.

Not only that, I’ve never tested any head that got anywhere even close to a discharge coefficient of 100%.
A head with decent flow at .100 lift rarely gets over 80%.

Up to the .300-.400 lift range, the flow is mostly impacted by the valve diameter, shape, and valve seat shape.
The TF heads have the same size intake valve, and a valve and seat shape that results in decent low lift flow.
At .100 lift…….they flow in the low 70’s(c/d of about 70%).

Even at .200 lift the SR flow sheet is showing a flow rate of over 100% c/d.
Keep in mind, it cannot be over 100%

The TF heads are about 76% at .200 lift.

If I flowed the OP’s heads here, I guarantee the flow numbers would be significantly different.
However, in its current form, the head flows what it flows, regardless of differing flow results from different benches.
Lower flow results from a different bench doesn’t make the head itself any less capable.

If bench A says 350, and bench B says 300……….for the same head………the dyno really doesn’t care.