New aluminum heads and extended RPM range

[blackford]

I hate to be the "naysayer" but, what is the average gain in airflow with your camshaft lift? That will be more in line with how much horsepower you can expect to gain. It has been my experience that if you don't change the camshaft, you will only gain 1 hp per cfm of airflow increase. I have yet to see the dyno results for the so called 2hp/cfm increase unless you have over 13:1 compression, and tunnel ram intake. JMO, but to see triple digit increase will not happen unless you change more than the heads. Joe-71

I know it's surprising. The old heads probably flowed 220 cfm or so. The new heads are 60 cfm better. I'm wondering though what the old heads really flowed at 7000 rpm where they were most likely choking. Here is the EA Pro printout showing the HP increase in red

EAPro03212023.jpg

[BobbyB]

I hate to be the "naysayer" but, what is the average gain in airflow with your camshaft lift? That will be more in line with how much horsepower you can expect to gain. It has been my experience that if you don't change the camshaft, you will only gain 1 hp per cfm of airflow increase. I have yet to see the dyno results for the so called 2hp/cfm increase unless you have over 13:1 compression, and tunnel ram intake. JMO, but to see triple digit increase will not happen unless you change more than the heads. Joe-71

I know it's surprising. The old heads probably flowed 220 cfm or so. The new heads are 60 cfm better. I'm wondering though what the old heads really flowed at 7000 rpm where they were most likely choking. Here is the EA Pro printout showing the HP increase in red

EAPro03212023.jpg

Wow! big increases up top. I am surprised it shows small losses below 4500 rpm... are you surprised to see the losses?

[blackford]

I hate to be the "naysayer" but, what is the average gain in airflow with your camshaft lift? That will be more in line with how much horsepower you can expect to gain. It has been my experience that if you don't change the camshaft, you will only gain 1 hp per cfm of airflow increase. I have yet to see the dyno results for the so called 2hp/cfm increase unless you have over 13:1 compression, and tunnel ram intake. JMO, but to see triple digit increase will not happen unless you change more than the heads. Joe-71

I know it's surprising. The old heads probably flowed 220 cfm or so. The new heads are 60 cfm better. I'm wondering though what the old heads really flowed at 7000 rpm where they were most likely choking. Here is the EA Pro printout showing the HP increase in red

EAPro03212023.jpg

Wow! big increases up top. I am surprised it shows small losses below 4500 rpm... are you surprised to see the losses?

I figured it was because the smaller ports of the old heads promoted more torque at the lower rpms.

[Tom68]

I know it's surprising. The old heads probably flowed 220 cfm or so. The new heads are 60 cfm better. I'm wondering though what the old heads really flowed at 7000 rpm where they were most likely choking. Here is the EA Pro printout showing the HP increase in red

EAPro03212023.jpg

Wow! big increases up top. I am surprised it shows small losses below 4500 rpm... are you surprised to see the losses?

I figured it was because the smaller ports of the old heads promoted more torque at the lower rpms.

Or stifled torque through most of the rev range.

[BobbyB]

Wow! big increases up top. I am surprised it shows small losses below 4500 rpm... are you surprised to see the losses?

I figured it was because the smaller ports of the old heads promoted more torque at the lower rpms.

Or stifled torque through most of the rev range.

What do you mean, Tom? Do you not think His simulation numbers are accurate?

[Tom68]

Nah good but there's more ups than downs with the better flow.