Ported Ford 289 heads with port energy discussion

[Carnut1]

Brand new Manley with short 30 degree backcut I think.

[Smoke ring]

Got an oem valve that size you can try?

[Carnut1]

Got an oem valve that size you can try?

No, But I do have a non backcut new manley 1.85"

[Carnut1]

20170814_191621.jpg

New Manley 1.85" valve with large back cut. I also flowed the intake and exhaust with non back cut valves. Intake lost up to .4" lift and gained a full 6 cfm up top. Exhaust valve without back cut did not have a radiused face. Lost flow up to .4 " and had very slight gain after that lift.
Thanks, Charlie

[Carnut1]

Resized_20170816_200736.jpeg

65 289 heads cut for 1.85"/1.6" valves. My attempt to beat my last pair of 289's with better port energy has failed. I could not come close to the flows and the port is nearly identical in cc. I think the reason is I pushed the original set pretty close to the casting limits, or past in one instant. Even with the smaller valve I was afraid to go too thin on the ssr. I need to cal DV in a few days I might be able to save these moving to a 1.94 with DV valve job angles. It seems after each flow test, flow ball and Pitot test they started to look more like the last set. At least I am consistent that way. Thanks, Charlie

[Carnut1]

0820171655c.jpg

Finishing up the 65 289 1.85" /1.6" set. Slightly different chamber mods. Intense sonic work trying to beat 1.94" set. Still keeping min .125" thickness intake into water and more near exhaust port. Exhaust is thick except few spots in bowl .135". Input welcome. Thanks, Charlie

[randy331]

Intake lost up to .4" lift and gained a full 6 cfm up top. Exhaust valve without back cut did not have a radiused face. Lost flow up to .4 " and had very slight gain after that lift.

Do you consider that a win ?

Randy

[Carnut1]

On a .625" lift cam I am not sure but I may try to sell it to DV. If these have a similar high lift flow to the E7's but are way down on low lift flow it might make for some interesting testing. I am thinking these will be down on power. Thanks, Charlie

[turbo2256b]

On a .625" lift cam I am not sure but I may try to sell it to DV. If these have a similar high lift flow to the E7's but are way down on low lift flow it might make for some interesting testing. I am thinking these will be down on power. Thanks, Charlie

Have seen a 10 or 20 HP increase but loose more than twice that at lower RPMs when the low lift flow drops.

[CGT]

On a .625" lift cam I am not sure but I may try to sell it to DV. If these have a similar high lift flow to the E7's but are way down on low lift flow it might make for some interesting testing. I am thinking these will be down on power. Thanks, Charlie

Have seen a 10 or 20 HP increase but loose more than twice that at lower RPMs when the low lift flow drops.

So low lift flow makes low end power now?

[randy331]

On a .625" lift cam I am not sure but I may try to sell it to DV. If these have a similar high lift flow to the E7's but are way down on low lift flow it might make for some interesting testing. I am thinking these will be down on power. Thanks, Charlie

Likely the 2 heads would have differences besides what's seen on the flow bench, making a conclusion about the flow itself incorrect.

Dyno them with no back cut, pull the heads and do just a back cut and re dyno.

Preferably in and ex back cuts separately.

Randy

[Carnut1]

This will be between 6 or 7 sets of heads on one shortblock so multiple pulls with one set of heads will not be practical. Thanks, Charlie

[MadBill]

Since the optimum cam will likely be head-specific to some extent, will each of the latter be paired with its matching COS cam, at least for LCA?

[mag2555]

Many times you just have to see what the motor wants in regards to where in the rpm range you want the power band to have the most girth!
Have more low lift flow Intake port wise will always drop the rpm where the port becomes velocity blocked because your already moving more air thru the port earlier at a lower lifts, that is if the motor can make use of the added low lift flow.

Excess air flow available before the descending piston gets to within 75% of its peak FPS down the Bore can at times buy you nothing power wise!

[randy331]

Have more low lift flow Intake port wise will always drop the rpm where the port becomes velocity blocked because your already moving more air thru the port earlier at a lower lifts, that is if the motor can make use of the added low lift flow.

How much testing have you done to validate this ?

I've found choke rpm is mostly CSA and bore/stroke related, and port shape ( expansion rates etc ) and what I see on the flow bench cfm wise, is of very little value in determining the heads rpm potential.

Randy