[Baron Von Zeppelin]

Also from McCarthy test
@.500 lift = 200cfm intake and 150cfm exhaust.


PY member just did a faithful stock spec type rebuild on a 70 IV for a real IV TA resto.
Made 398 HP on a dyno through manifolds.
The 200cfm number doesn't seem too far off on a 400hp engine.
with a cup of coffee and a donut.

[PAUL K]

Originally Posted by Baron Von Zeppelin

Also from McCarthy test
@.500 lift = 200cfm intake and 150cfm exhaust.


PY member just did a faithful stock spec type rebuild on a 70 IV for a real IV TA resto.
Made 398 HP on a dyno through manifolds.
The 200cfm number doesn't seem too far off on a 400hp engine.
with a cup of coffee and a donut.

Pete's numbers were consistently accurate printed in HPP. He did us all a huge favor. The specified numbers are difficult to compare to any other flow tests due to an issue with the equipment.

Pete's numbers 200/150 show a 75% intake to exhaust ratio. That pretty close to other stock RAIV flow tests.

Don's 200/180 shows a 90% I/E ratio ..... Something is askew with Don's numbers..... It raises a flag. Not saying they're not accurate but for some reason the intake flow is extremely low, or the exhaust high. More information is needed.

398 HP seems like legitimate numbers. Your 200 CFM number is most likely coming from total flow through the induction system. That usually needs to be considered on a street build since the the port is usually not the most restricted part of the intake tract.

SuperFlow offers this equation to estimate power; induction system total CFM @ 28" x .598 x .43 x the number of cylinders. If you plug in your 200 CFM number I think your close to the 398 number.... With headers he'd probably be right there.


PONTIAC'STTFMF's!!!

[Steve C.]

"My head flows more rats than your head"

A tid bit for interest, and one that relates to Paul's comment....

" The specified numbers are difficult to compare to any other flow tests due to an issue with the equipment."

The issue was a mouse nest, or rats nest depending on the story, that was inside Jerry Goodale's flow bench at the time of Pete's cylinder head testing.
Unknown at the time it affected the flow numbers. That said, If the nest was in there for the duration, then the numbers were at least relative to each other.


.

[Steve C.]

Another important comment from Paul....

"Your 200 CFM number is most likely coming from total flow through the induction system"

And related. Air Flow Research developed a formula based on air flow. It predicts a normally aspirated engine's horsepower potential based on intake-system airflow.
It is based on the net cfm airflow delivered at the valve thru the carb, intake manifold and cylinder head. Not the cylinder head cfm flow itself. The formula.....

Horsepower = 0.25714 x cfm at 28" x number of cylinders

There are some caveats involved. Actually reaching the predicted power level requires the engine to have the right compression, the right cam, a tuned exhaust, and a nonrestrictive carb and intake manifold.
The combined lift generated by the cam lobe and rocker arm should equal the observed lift on the flow bench needed to achieve the desired intake port flow, plus a good exhaust port flow. Etc, etc.

( Information provided in this post does not represent any endorsement of the formula stated and is offered for general interest only )



.

[johnta1]

old DCI thread

[b-man]

Originally Posted by johnta1

old DCI thread

Discussion in the Race forums where he begins by outlining all the traits of a Pontiac V8 engine design that makes it less than ideal as a serious race engine.

So there’s little relevance in that thread to this discussion about his new heads that aren’t designed for full-on race applications, other than to point out the comments that Pontiac people are reluctant to open their wallets which unfortunately is true in many instances.

Very few posts here in the last 5 years, the majority of those being classified postings either selling or looking for parts.

Introduction of his new cylinder head project would have welcomed here just as was done in this Lobby thread where an innovative new product was warmly received. Plenty of questions were asked and answered and criticism offered without getting any feelings hurt:

https://forums.maxperformanceinc.com...d.php?t=871015