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Old 11-25-2009, 09:36 AM   #1
Valve body
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Default Rec port intake on Oval port head

Hey guys,
Does anywhere here have any info on putting a rectangular port intake on a oval port head? This is for a BBC.

If you knew the maxium diameters you could port, you could kind of make a "roval" port on the oval BBC head..

Thanks
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Old 11-25-2009, 09:45 AM   #2
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Default Re: Rec port intake on Oval port head

What's the application.
Need more info.
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Old 11-25-2009, 12:56 PM   #3
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Default Re: Rec port intake on Oval port head

It will be 468 BBC, 12-1 to 13-1 compression

049 cylinder heads 2.19 1.88 valves

Comp camps solid flat tappet .638/.631 lift, 270-276 duration @50, 108 LSA

in a car weighing 3800 lbs, gear likely a 4.11-4.88, likely a 4500 stall, 28 inch tall tires

potentially a Offenhausen Super Sonic intake with rectangle port

potentially a Dominator 1000 cfm carb with annular boosters

This will be racing in the 1/8 mile
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Old 11-25-2009, 01:58 PM   #4
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Default Re: Rec port intake on Oval port head

In spit of the "eeuw.....it just ain't right" factor, I think it's best not to change the port entry to try to blend the head to the manifold. I have seen this miss-match work well so many times I quit thinking it "just ain't right". I suggest you leave it alone and run it.

In the 70's there was a common 460 Ford marine engine in jet boats that Ford produced with standard Cobra Jet heads and a Super Cobra Jet cast iron intake. The mismatch is similar to the BBC square/oval deal. A hotrod boat magazine did a series of articles about modifying the 460 with dyno results. One of the eye opening deals was when they bell-mouthed the port entry to match the intakes they tested, the stock Ford iron Holley 4150 intake, the aftermarket tunnel rams or Offy Port-O-Sonic, they all ran much worse. I forget the power numbers, but it was a lot, like 75 HP. In one of the tests, they (Mondello, I think it was) did two sets of heads, both with similar bowl work and exhaust port work, one with the intake port bell-mouthed for manifold matching and the other left as-cast. After they first ran it with the matched heads and the power took a dump, they did another pair without the port-matched intake, with just the bowl and exhaust work, and that turned out to be the much better deal in the end. Just another one for the "who would have thought" locker.

460 Ford still couldn't keep up with the 454 Chevy.
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Old 11-25-2009, 02:18 PM   #5
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Default Re: Rec port intake on Oval port head

just use a rect port intake gasket.
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Old 11-25-2009, 02:22 PM   #6
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Default Re: Rec port intake on Oval port head

Yes I was wondering that too, for some reason I heard that it is best to leave it "more mismatched" rather than try to modify the port entry. I am unsure of the scientific explanation is for this...

I guess it would still be worthwhile to gasket match the heads to a standard oval port gasket. for a future intake swap...Like I am trying to do here..

http://www.chevelles.com/forums/showthread.php?t=298302


Side question; is this the standard amount of material that needs to be removed in a 049 application?


I am on a really tight budget so I might just pick up this intake and then later on buy a nice new Team G one. The head will already be port matched for a oval gasket..

Thanks
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Old 11-25-2009, 03:05 PM   #7
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Default Re: Rec port intake on Oval port head

I'd leave it alone for now. Wait until you have the manifold because you might see it different looking at both the heads and manifold at the same time. Besides, the as-cast rough wall encourages vaporization of the fuel. Save yourself a lot of work on something that probably couldn't be measured on the time slip. Wasted time slip, maybe.

Like the guy in the thread you linked, I would not be hasty to match anything to the first gasket set on hand, especially without the manifold to compare. You can't grind it back when it's gone. I've seen different brands of the "same" gasket that didn't fit each other.

Anybody know whatever happened to Detroit Gasket? They were the gasket supplier of OE GM (and probably the others) in the good ol' days.

The car will be faster if you spend the time working on the suspension.
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Old 11-25-2009, 04:01 PM   #8
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Default Re: Rec port intake on Oval port head

Hey thanks Yeti,
It was actually recommended of me to increase my power because my suspension is working well right now..

http://www.yellowbullet.com/forum/sh...d.php?t=142216

Yes I think I will start off by doing some basic cleanup and then when the manifold arrives I will change my porting tasks..
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