Oval Port heads with Retangular Port Intake?

[Ken's67]

I have a working '66 427 motor with 3872702 heads. (I think they have Oval Ports) I want to remove the current intake, 3933163 and replace it with a
3885069. I think the 3885069 intake has rectangular ports. Can this be done? And will it run O.K.?
I just found some information on the current intake 3933163, It looks like this has rectangular port also. This car had rectangular intake and an oval heads. It ran great. I would like the opinion of other on this setup. Thanks.

 

[67HEAVEN]

Ken's67,

Although not the optimal situation, they'll run fine together.

 

[Tom Bryant]

Yes your heads are oval and the 069 intake is rectangular. It was used on '66 427/425 and '67 L88s. If you just want to install it for looks and assuming it will seal it should run fine. The port mismatch will surely wipe out any performance gains from the manifold design though. Running a large port into a small port head with a different shape will leave a ledge around the port where they mate up that will raise havoc with the air flow. If it was the other way around....small port into a large port head, it wouldn't be that much of a deal. You would just loose velocity downstream. You may have to compare both a rec port and an oval port intake gasket against both head and intake to be sure there are no areas that won't seal. I'd try to use the rec port gasket first.

Also remember that that big port intake was designed to perform from around 3500 rpm on up with a radical cam. It will be a slug on your engine. Expect dead tip in and sluggish low rpm response. If you are just looking to improve performance then an Edelbrock Performer RPM for oval ports will leave that missmatched intake in the dust. I'm not just talking about the port missmatch but also the advances in tecnology in the nearly 30 years since that 069 was cast. Add to that the right hyd. performance cam and hang on!

Tom

 

[henny496]

Oval ports

Hello
A good oval port intake will give you lots of power where you want it. Rectangular port heads and intake will make more power, but the power band is much higher than an oval port system as Tom Bryant mentioned
I have oval heads on my old drag motor and I have killer ported aluminum D-port heads for my blower motor. The D-ports heads would destroy all bottom end power on my normally aspirated 427 and I probably would not make any power until after 5,000 rpm
If you can , I would reccomend using a good oval port intake
Tom
You want your motor to be making power in the rpm range your motor is operating at.

 

[wildbill486]

dude...

it's all about the idle sound...