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 redJoe-71 wrote: ↑Tue Mar 21, 2023 12:44 pm 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
New aluminum heads and extended RPM range
Moderator: Team
Re: New aluminum heads and extended RPM range
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65 Mustang FB, 331 custom built with 289 H beam rods and 383W piston, 282S cam, Ported Maxx 180s, T5z, 9" 3.89 gears. ~460HP@6500
2013 Corvette 427 Convertible daily driver
2013 Corvette 427 Convertible daily driver
Re: New aluminum heads and extended RPM range
Wow! big increases up top. I am surprised it shows small losses below 4500 rpm... are you surprised to see the losses?blackford wrote: ↑Tue Mar 21, 2023 1:46 pmI 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 redJoe-71 wrote: ↑Tue Mar 21, 2023 12:44 pm 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
EAPro03212023.jpg
Re: New aluminum heads and extended RPM range
I figured it was because the smaller ports of the old heads promoted more torque at the lower rpms.BobbyB wrote: ↑Tue Mar 21, 2023 1:57 pmWow! big increases up top. I am surprised it shows small losses below 4500 rpm... are you surprised to see the losses?blackford wrote: ↑Tue Mar 21, 2023 1:46 pmI 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 redJoe-71 wrote: ↑Tue Mar 21, 2023 12:44 pm 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
EAPro03212023.jpg
65 Mustang FB, 331 custom built with 289 H beam rods and 383W piston, 282S cam, Ported Maxx 180s, T5z, 9" 3.89 gears. ~460HP@6500
2013 Corvette 427 Convertible daily driver
2013 Corvette 427 Convertible daily driver
Re: New aluminum heads and extended RPM range
Or stifled torque through most of the rev range.blackford wrote: ↑Tue Mar 21, 2023 3:21 pmI figured it was because the smaller ports of the old heads promoted more torque at the lower rpms.BobbyB wrote: ↑Tue Mar 21, 2023 1:57 pmWow! big increases up top. I am surprised it shows small losses below 4500 rpm... are you surprised to see the losses?blackford wrote: ↑Tue Mar 21, 2023 1:46 pm
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
Ignorance leads to confidence more often than knowledge does.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
Re: New aluminum heads and extended RPM range
What do you mean, Tom? Do you not think His simulation numbers are accurate?
Re: New aluminum heads and extended RPM range
Nah good but there's more ups than downs with the better flow.
Ignorance leads to confidence more often than knowledge does.
Nah, I'm not leaving myself out of the ignorant brigade....at times.
Nah, I'm not leaving myself out of the ignorant brigade....at times.