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Sit N' Spin
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OK...so here I go reading the threads on rec. port heads, and I get guys flaming oval port heads as if there's only one type of oval port head and that they all suck.

First off, for those of us who are new to BBC's, there are TWO types of oval port heads: small oval port (aka "peanut" port) and large oval port.

Small oval port heads are very common on heavy cars and trucks. These heads feature high port velocity at lower RPMs for making some good bottom end torque. Up around 4500RPMs, they start to choke the motor and are not suited for building horsepower much above that.

Large oval port heads offer the best of both worlds, building low end torque while allowing the motor to breathe up to a much higher RPM. It is my understanding that large oval port heads are good up to about 6500RPM if you fit them with larger than stock valves.

Now I remember speaking to Chris awhile back in a PM about the large oval port heads, more specifically the casting '353049' heads which I find on a lot of jet boats. Chris had flat out told me that the '049' heads are capable of making some serious power. Was hoping Chris could come onto this thread and save the fate of large oval port heads and give us some facts about them as well as disspell the myth that large oval port heads will choke the motor around the RPMs we spin them in a jet.
 

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steelcomp was here
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This has been gone over and over and OVER and OVER and over....
No one's ever said oval ports won't make power, or aren't capable of making power. They're just limited, depending on application. Heck, a set of 360's is limited at some point.
It's all about the combination. Heads by themselves mean very little.

BTW there's a third set of oval porst fo BB Chev...:|err:)hand
 

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The 049 and the 781's are capable of making 700 HP in high compression 468 CID engines. I've done this over the las 10 years in truck pull engines where the rules limit these engines to solid flat tappet cams, OEM blocks, and OEM heads. These heads go through extensive port work including some with welded ports. These heads when done regularly have about $5 to 7K of work and parts but are neccessary to compete in the class.

Would I recommend any recreational boater to spend $5K on OEM heads when he has access to very good aftermarket heads at half the price. . . .NO. I feel for anyone on a budget that has a set of these casting laying around and want to make a 500HP engine, you will have minimal investment in modifications to the heads and good bang for the buck. Anyone who wants to make 700HP with a set of these heads I will give you a couple of telephone numbers to head porters and you better get the Visa card out becasue they don't take American Express.
 

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This book discusses the topic...has some decent combos included also...



High HP is also relative to each individual...I consider my build to be fairly high power but also built to be reliable and last. A lot of guys here would probly laugh at my power level too...I'm nowhere near 1000 HP!!!
 

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steelcomp was here
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I can install larger valves, freshen the guides, multi angle valve job and even some mild portwork (just don't like grinding cast iron any more) and get a set of these oval porst working real nice.
In fact, I'm going to build up a set here in the next few days. I'll post some pics of the re-work so you guys can see what goes into them.
 

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steelcomp was here
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this very thing was bought up in bocco's thread, "????about rect heads." Like cstraub posted, it's all about the money you are willing to spend. For the money I spent on a set of 049 ovals 15yrs ago, would almost buy a set of canfields today, and the canfields would kick their ass.
Almost...yes it would take some pretty serious $$ to get a set of 049's working as well as a set of Can's. but I don't think that's then idea here. Work with what you got, make the best out of them within reason, cam accordingly, and go.
 

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Or Seth, either one
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I can install larger valves, freshen the guides, multi angle valve job and even some mild portwork (just don't like grinding cast iron any more) and get a set of these oval porst working real nice.
In fact, I'm going to build up a set here in the next few days. I'll post some pics of the re-work so you guys can see what goes into them.
YES, please do. I have these heads too and noticed a lot of casting flash in the ports. I'm very curious what it would take to clean them up a bit myself and what possible gains may be. Mine sit on a 396.
 

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I'm famous !
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Almost...yes it would take some pretty serious $$ to get a set of 049's working as well as a set of Can's. but I don't think that's then idea here. Work with what you got, make the best out of them within reason, cam accordingly, and go.
I agree, we just didn't have the options then. Just stating that there is a point of demishing return when working with any stock head. What you were suggesting for a set of stock ovals is as far as I would go now, and they a great for most medium builds, but any more work than that is just a waste of time and money. IMO



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A bunch of years ago I used to hang around a shop that did a lot of work on NHRA Super Stockers. One pretty sharp guy (currently runs Ben Watson's Pro Stock engine program) did a lot with oval port heads in low compression, cast crank 454's. He was making over 600 HP back then, but doing a bunch of crazy stuff with cams. We tried several of his tricks on our basic 509" aluminum head, high compression, bracket motor and went backwards every time. My point is there's lots of ways to make HP, just depends on how much work & money you want to throw at it.
 

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If a person had a set of 049's an 990's laying on the shelf and you wanted to do a 600+ hp 454 why would anyone chose ovals?? Seriously? I'm not saying that anyone who posted here would choose them..... Oh shit give me a bigger shovel so I can dig a deeper hole.
 

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If a person had a set of 049's an 990's laying on the shelf and you wanted to do a 600+ hp 454 why would anyone chose ovals?? Seriously? I'm not saying that anyone who posted here would choose them..... Oh shit give me a bigger shovel so I can dig a deeper hole.
Just putting huge Rect Port heads on a motor doesn't promise you anything Smaller port AFR heads actually flow better than a lot of much bigger port aftermarket heads. But its done with velocity. The same applies to oval port Chevy heads. If you do a decent not even too wild port job on them, they flow well, and can support HP and RPM. The last set I ran were on a 454, and made well into the 600 HP range. and spun 6000+ RPM with acceleration that kicked you back in the seat.

Just dumping air into cylinders with no velocity on a NA motor is a waste of time and money. and its a mistake too many people make
 
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