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Adger Smith · 03-21-2011, 11:55 PM

Art,
sorry I missed your call tonight. I was fooling around, getting my car ready to load.
as for the intake/ head deal.
I will assume you tested 2 different head/port size combinations with the same intake.
If you did that and one head made more torque than the other it is probably because the intake restricted the bigger cross sectional head. I have seen good heads be choked by an intake.
Untill proven wrong by testing I take the approach that it is better to have the smaller head and use an intake that has some taper or larger port size that will not make the head loose flow when testing with the intake installed.
If the velocity of the small port is right it might pull harder and accelerate quicker than the larger vol head with a non restrictive intake.
A small ledge at the head intake port junction can cause a slight tumble/waterfall effect in the head port. Sometimes this is good because it will help keep fuel in suspension with the air even though the tumbling air makes the port see it's self as a smaller cross sectional. Sometimes if the veolicity is real high it will not waterfall as good and will shear the fuel out of the air. You will see that by having poor combustion and needing a severe jet change.
Now, where is the mismatch?
The high flow area is usually at the top of the port. If you have a mismatch it is usually better to have it on the bottom of the porrt. Can you slot the mounting holes and move the intake to where you have less or no mismatch at the top? If you have a mismatch on the walls it is best to position the intake where the inside wall is mismatched and the outside wall is lined up. What Alan suggested is a good way to fix it. Just make the epoxy trasition go way back into the intake. This is like building taper. No abrupt cross sectional changes allowed!! You want to stay away from building a hook at the end of the intake runner. That is real bad for flow.
I think I would try to line it up on the small/High Tq head as good as possible and see if it helps. That way you are testing the intake, not the heads.
Call me tomorrow. I've got a couple of other ideas, but it's time to give the pillow my head...
Adger

03-21-2011, 11:55 PM	#7
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Intake manifold to cylinder head? Art, sorry I missed your call tonight. I was fooling around, getting my car ready to load. as for the intake/ head deal. I will assume you tested 2 different head/port size combinations with the same intake. If you did that and one head made more torque than the other it is probably because the intake restricted the bigger cross sectional head. I have seen good heads be choked by an intake. Untill proven wrong by testing I take the approach that it is better to have the smaller head and use an intake that has some taper or larger port size that will not make the head loose flow when testing with the intake installed. If the velocity of the small port is right it might pull harder and accelerate quicker than the larger vol head with a non restrictive intake. A small ledge at the head intake port junction can cause a slight tumble/waterfall effect in the head port. Sometimes this is good because it will help keep fuel in suspension with the air even though the tumbling air makes the port see it's self as a smaller cross sectional. Sometimes if the veolicity is real high it will not waterfall as good and will shear the fuel out of the air. You will see that by having poor combustion and needing a severe jet change. Now, where is the mismatch? The high flow area is usually at the top of the port. If you have a mismatch it is usually better to have it on the bottom of the porrt. Can you slot the mounting holes and move the intake to where you have less or no mismatch at the top? If you have a mismatch on the walls it is best to position the intake where the inside wall is mismatched and the outside wall is lined up. What Alan suggested is a good way to fix it. Just make the epoxy trasition go way back into the intake. This is like building taper. No abrupt cross sectional changes allowed!! You want to stay away from building a hook at the end of the intake runner. That is real bad for flow. I think I would try to line it up on the small/High Tq head as good as possible and see if it helps. That way you are testing the intake, not the heads. Call me tomorrow. I've got a couple of other ideas, but it's time to give the pillow my head... Adger __________________ Adger Smith (Former SS) Last edited by Adger Smith; 03-22-2011 at 12:21 AM.