Hi!
Iam running a 427 with peanut port -#360 heads with 2.125" intake valves. Ported To flow 300 at 050. NO portmaching! Stock rect alu 425hp high rise intake.
224/230 sft Comp cam.
Car: Caprice 4 door -67.
Pulls hard off idle to 6k.
450hp+ 5200-5700 on correkt dyno.
Why? Like the velocety from the small intake port and the stock look of the 'fireing order' GM intake!
(Or helps me when putting back the pluggwires. )
Rgds
Burt
Rectangle port Intake on Oval port Heads
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Re: Rectangle port Intake on Oval port Heads
Last edited by Old Viking on Thu Oct 06, 2016 8:05 pm, edited 1 time in total.
Old Iron Still Rocks
Re: Rectangle port Intake on Oval port Heads
The instructions clearly stated the port mis match was intentional and matching would be detrimental.
I had that intake manifold (Edelbrock Tarantula Oval port) and I do remember that cast in port mismatch and the note about that.
Back then ,like you, I should have tried the OEM (LS6, L72, L78)square port dual plane high rise on my oval port 454. There was very few intake manifold choices for oval ports back then.
The 66 396 cast oval port high rise dual plane (holley flange) was not very good for power. And the Torker 2-O sucked too.
I had that intake manifold (Edelbrock Tarantula Oval port) and I do remember that cast in port mismatch and the note about that.
Back then ,like you, I should have tried the OEM (LS6, L72, L78)square port dual plane high rise on my oval port 454. There was very few intake manifold choices for oval ports back then.
The 66 396 cast oval port high rise dual plane (holley flange) was not very good for power. And the Torker 2-O sucked too.
Re: Rectangle port Intake on Oval port Heads
Back in the mid-seventies I had the rectangular version on my 495. Its instructions also cautioned against correcting the (huge) mismatch. In retrospect, selling my like-new L88 manifold in favour of the Tarantula was not one of my best moves...
Felix, qui potuit rerum cognscere causas.
Happy is he who can discover the cause of things.
Happy is he who can discover the cause of things.
Re: Rectangle port Intake on Oval port Heads
The thought just popped into my mind... any chance of the guy who posts all the CFD sims on here putting something together to model this effect?
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Re: Rectangle port Intake on Oval port Heads
Has anyone on here used the Edelbrock Performer RPM 60435 100cc "Oval" or "Roval" port heads with a rectangle intake?
I have a 496 BBC the combo was originally built with closed Chamber 840 rectangle port GM heads. I want to use the 60435 heads to keep the 100cc combustion chamber & have a Victor 454R intake with Endurashine I would like to keep/use if for nothing else its looks.. . Buying another intake is an option. Just wondering what your thoughts are. These are more of a Square port than rectangle, not really oval.
I have a 496 BBC the combo was originally built with closed Chamber 840 rectangle port GM heads. I want to use the 60435 heads to keep the 100cc combustion chamber & have a Victor 454R intake with Endurashine I would like to keep/use if for nothing else its looks.. . Buying another intake is an option. Just wondering what your thoughts are. These are more of a Square port than rectangle, not really oval.
Re: Rectangle port Intake on Oval port Heads
There have been a couple of S/T threads touting the surprisingly good results from pairing rectangular port manifolds with unmodified oval port heads. The obvious move of blending the ports to match the manifold, not so much...
Felix, qui potuit rerum cognscere causas.
Happy is he who can discover the cause of things.
Happy is he who can discover the cause of things.
Re: Rectangle port Intake on Oval port Heads
Based on a lifetime of dealing with flood waters and fishing in rivers I'm pretty sure that the big manifold small port combo will make more power than a small manifold into a big head port. The flow from the big manifold will create its own chamfer that varies with volume and the flow inside the head port will accelerate. With the small intake the edges of the intake will create eddys and whirlpools inside the head port which will disrupt flow.
Re: Rectangle port Intake on Oval port Heads
It would be interesting to see a straight up dyno test of a capable engine with oval port heads with say 2 tunnel rams on it
of same design, one being the rectangular port version and the other a oval port version.
of same design, one being the rectangular port version and the other a oval port version.
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Re: Rectangle port Intake on Oval port Heads
Thanks for the input. I am gonna try it. Nothing more than the cost of gaskets & intake down the road. I'll put this engine back in next month, we'll see how it works!