Chevy Aluminum Oval Port heads

[72 LS5]

Anybody of you guys run Chevy's new aluminum oval-port heads on your big block?

 

These are at the top of my want list. AFRs are way too expensive, otherwise I'd get those.....

 

These Chevy heads are supposed to be a great street head, outflowing most others with a streetable cam.

[dmdbit]

Are those heads the same as the edelbrock ovals?I thought I read that somewhere but can't remember for sure.Brodix has some new aluminum ovals that flow really well but like the AFR's are really expensive.

 

mike b

[Sam (Bones)]

I've got edelbrock on my 454, work great, they do or did make the G.M. heads, if I build a street big block, I'd use stock iron ovals, great torque & midrange, depending on what you want to do with it, and what gear you're using, sometimes smaller runs better

Sam

[72 LS5]

I have 71 oval right now with bigger valves. The newer casting flow so much better and the weight savings alone would be worth about .5 seconds.

 

Is that true about Edelbrock making heads for GM? I can't imagine why, since GM has everything they need, and the knowledge to produce their own heads.

 

I have a cylinder head shootout test (somewhere) that flows all the BBC heads and the Chevrolet aluminum oval edged out all the (oval) competition.

 

bones: so you say stick with irons? curious as to why?

[Sam (Bones)]

sometimes it's not about how much, in a car that's got a gear that's higher (2:73, 3:08, ect), smaller port, valve size, help keep velocities up, which helps throttle response, remember everything has to work together, on a setup like this a smaller carb is also better, on a car setup like this for street use how often does it see much over 4000 r.p.m.?, all this improves low end torque, driveability, you need to decide what you want first, my big blue barge runs 11.6's w/ a 3.73 rear, ovals, and a conservative cam, did I mention my 60' time are always under 1.55 w/ a best of 1.48

Sam

[Guest]

Sam hit the nail on the head for a street combo. On a non race app you must ignore peak flow and focus on the mid lift flow #'s and average flow #'s. Since most guy's run cams at less than .600 lift on the street a head that flow best above this sounds good and looks good on paper but won't work well. Its all a balancing act on a street combo. Even a car that sees some strip time is a street combo. If it drives to and from the track under it's own power some consessions are made so it can do this. This all said the Canfield 310 cc runner head has shown more velocity and has much better mid lift flow #'s than the Eddy ovals. Both the performer oval and performer rpm oval flow the same according to my eddy catalog. The Canfields are +16 int/+27 exh cfm at .400, +34/+37 cfm at .500, +38/+42 cfm at .600 and they keep gaining to .800 lift. On a decent 454 with the proper combo is worth way more power out of the box than the Eddy ovals can produce fully ported. The jegs brand aluminum heads are Canfields, and in the most current catalog they are $14 bucks per head cheaper than the Eddy's. Granted it would take a new manifold for the Jegs/Canfield heads but would cost less than the Eddy's + pro porting ($450+ on average) to full boat them for less flow and power in the end. Just something to think about if planning to buy a set of aluminum heads soon. For comparison The AFR 290's flow #'s are only 3 to 5 cfm diff, not enough to worry about. Did you notice that they aren't really oval ports! Just shorter than normal rectangular ports!. Special intake or manifold mods may be neede to make work properly.

Don

[Guest]

By the way the 375 hp 396 and 425 hp 427's were terrors on the street even in big cars! They had 305/310 cc runnered rec ports heads on them!!! With by todays standards crappy cam profiles and poorly designed ports and runners! The factory 310 runner dosn't produce but about the same flow as the Eddy ovals. The only way a runner of equal volume produces more flow is from velocity, which in turn ='s better cly fill and more power and torque. Even though you go up 20 cc from the ovals to the rec's the velocity at the tested lift points is higher to produce higher flow #'s when tested on the same bore fixture. Both the Eddy's and the Jeg's/ Can's were tested on superflow benches with a 4.31" bore adapter. I know this sounds maybe technical or preachy but it the things that seperate real engine builders from do it yourselfers and alot of wasted money. Some of use have had the luxury of O.P.M. and combo's to work. It saves alot of time and money on the personal stuff!!! LOL

Don

[72 LS5]

Bones and RR - thanks for your input, I appriciated it!

 

I realize that the ovals are the way to go no the street for the velocity reasons mentioned above. That's why I liked the Chevrolet aluminum oval - its a 290 cc head and flows extremely well with moderate lift cams. I wish I had the #'s in front of me, but I'm at work. You guys didn't mention anything about these heads, but I'm very interested in Bones running 11.6 with "Eddys" - what size cam are you running and what stall and carb? I'd like to run around 12.0 with 3.31 and a mild stall myself....

 

RR - I have a new interest in these Canfields. I will definately research these further. Will both the Canfield and Eddys accept a regular RPM O-port manifold with no modification? The ports do look square rathar than oval....

 

Thanks again.

[Guest]

The answer is no on both accounts. The Can's/Jegs deals are rec port at 310cc. The Eddy's are simply a smaller rec port head. The normally require a good bit of massaging of the intake to make it work. Even eddy's own oval port manifold is true oval like the factory. It takes someone with porting knowledge to work over and reshape the oval to small rec port at the head so as not to disrupt the flow. You can bolt up a std oval port manifold to the new eddy heads but the port mismatch will be quite severe and cause alot of turbulance. Which will cause a great loss in performance as well. For out of the box performance and room to grow down the road the the 310 can's/jeg's deals will work better. The object here is best bang for the buck correct? No ovals aren't always the way to go either! Its flow volume/port velocity/port volume balance that must be factored in. I can't remember your current combo, it would help to know. Alot depends on what you have now and what you want to gain and what might you do later? Put up some info for a more accurate response. Remember were not looking at factory designs here so the rules are different. If you were looking at factory rectang's verse factory ovals then yes it would be the ovals with the edge. Not so with aftermarket heads, the small rec's work killer on the street when the combo is correct.

Don

[72 LS5]

I was going to do a similar combo as this:

http://www.compcams.com/Community/Articles/Details.asp?ID=-1972547497

 

And here is where I was getting flow numbers, unfortunately no Canfield 310, just the 305. As far as the o-ports go, the Chevy looks great. Canfields even more so, but I'm worried, because on paper, it sure seems that velocity would be too low.

http://www.chevyhiperformance.com/techarticles/41598/

 

OK, so we know how well the heads flow, so how can we measure velocity for maximum cylinder filling?

[Guest]

Velocity is a function of flow if all test's are done under the same conditions. Since Eddy and Canfield both used the same make and model of flow bench with the same bore size fitting at the standard test press of 28" of water press. Then the results show which is better, for one head to have 30+ cfm more flow for only 20cc more runner shows it moving more air at the same draw as the smaller head and doing so much more effeicently. Can velocity be measured like flow on a bench? NO. Have I personally worked with both heads? Yes. I replaced a set of performer ovals ported by some shop, don't know who, looked good but, checked ok on the flow bench. Best I can remember ports checked out at 300 cc and only was up about 7 cfm over the claimed eddy flow. Swapped the heads manifold.Engine made 560hp and 565ftlbs on pump gas after the swap. Before best pull was 510hp and 530ftlbs. Combo was a 10.4 to 1 .030 454, xe274h cam. Canfield heads and vic jr r were only gasket matched, 800 cfm carb 2" into 3.5' headers. 3600# 70 chevelle. If this is what you are looking for then just duplicate the combo. No I did not build it the first time the owner bought the complete engine from a "shop" in Indy. There was more to be gained from a better cam. But the guy wanted to leave the cam for now. Maybe upgrade later when he gets bored with it. That shop must have copied the article almost to a T!!!! The info in the head article is old most of those heads have under gone redesigns and updates since then. The combo I told you about was done the first of december 2005, the original was built in sept all current stuff. Those magazine guy's are not pro's! They just get free parts to play with!!!

Don

[Sam (Bones)]

I said it before, and I'll say it again, DON, YOU DA MAN!!!!, when it comes to engines, I'll do what Don tells me, when I get my '71 back I'll be putting it back together and taking it apart at the same time, Don gave me a cam grind to try and a intake, I also need to talk to him about my heads and where I'm going w/ this car, I know it's not very streetable anymore but, I WANT lower 11.'s, not interested in hittings 10's

Sam

[72 LS5]

Don, thanks for the reply.

I would hope that the guys doing the flow bench would be professional. If every test in a magazine is giving questionable data, then most people can't base their selections on anything.

 

The power numbers you mentioned sound more than I had hoped for with the XE274. That's unreal that you got another 55 hp from the heads and manifold. Now I have some new questions. Obviously one would think that the big ports would give away some low end torque. Were the power numbers just moved up the rpm scale? I'd like to keep the stall under 2800 and the gear at 3.31. Would I still have the torque down low? What about intakes - would a dual plane run better with the Canfields? I hate to meantion dyno tests again, but nobody has seen better average hp number than with the RPM on a street engine. You seem to like the Victor. Do you remember the carb size on that engine?

I appreciate the discussion.

BTW What does Rice Racing1 mean???

[Heckeng]

Ok, I'm going to be a little bit of a Devil's advocate here! Why is everybody stuck on ovals? I say don't believe everything you hear. I know, everybody says that ovals are the way to go on the street, but I have a 454HO in mine and it has the Chevy 325cc Rectangular port iron heads, and it does great on the street, no bogging or waiting for the engine to catch up with iself. I only have a B&M 2400 hole shot converter, and 3.55 gears with a 28" tire. It also ran a 12.75 in the quarter at 106mph. When I find my time slips I will post the 60' time. I was surprised that It did as good as it did, but I think that the theory of oval for the street and rectangular for race has been blown out of proportion. Just don't get huge heads, with a tiny cam and highway gears and you'll be fine in my opinion. I say dump the cash on the 305cc AFRs, and if you get some extra money, get the chamber CNC option. I have also heard good things about Canfields as mentioned above. A friend put on some Edel RPMs on his ford, and they seemed very quality built also.

 

I have also heard that Edelbrock makes the high performance heads for Chevy. Just the same as MSD making the GM high performance ignition that you see in the catalog.

 

On the blown out of proportion myth topics, I also just switched out my 750 vac sec holley for a 750 speed demon double pumper, and it is doing fine! I was worried because you always hear "never run a double pumper on a heavy car" or not on the street, but it is working fine. I haven't had it at the track yet to see how it reacts with slicks, but on the street it is a hoot so far. Sorry for the subject change there!

[Sam (Bones)]

Don,

when you told me to use the victor jr intake w/ my edel oval heads, should it be a oval or a square model? then have it port matched? my heads are out of the box, untouched, right now w/ a air gap oval

thanks Sam

[Heckeng]

Match your intake style to your head style or vice-versa . I've not heard of anyone porting one style to match the other, interesting idea but I doubt it would work or be worth the effort.

[72 LS5]

Heckeng: I think what Bones was referring to is that the Eddys aren't true ovals, like mentioned earlier in the post. The are more like a square, so any oval port intake would be somewhat of a miss-match.

[Heckeng]

Oops, after looking back now, I see what you are saying. Sorry, didn't catch it originally. my bad!

 

I don't understand why they would make a runner design that would not match any intakes, knowing ahead of time that the heads are always going to have a transition flow loss that would more than likely kill off any of the good flow work that they had designed into the heads. Somebody please enlighten me.

[Guest]

Sam, use the oval and open it up to match the head, blend the transition at least 1.5" back up the runner.

 

72LS5, Where to begin. Magazines guy's don't have the equipment to verify the flow numbers they just go buy what is sent with the heads. You don't believe that any high volumne manufacturer will simply go to the shelf pull parts at random and ship them for nationwide mag build up do you? Those components aren't what you get when you order, they may go through 100 sets of heads looking for the best ones, then they will be plue printed and have the bowls "cleaned up". So no the mags don't lie they just don't tell you the whole story. As for the The large gain in power on the combo I pointed out it was due to the more effective head manifold combo letting the engine breath properly. Port velocity is a double edged sword, too much is worse than not enough! Too much creates turbulance along the walls of the runner due "sonic shear" which means it heats the boundry layer of air to the point it becomes unstable. How many times you heard guy's say I built it just like the MAG ART but mine doesn't run like theirs? They always seem to follow that "those guy's are just better tuner's than me or I must have done something wrong."

The carb was an 830 cfm annular discharge holley DP. List # on the carb was 0-9831. The mag guy's aren't there to guide you along, They only want to sell mags and advertising space.

As for the login its just what I tyoed in at the time.

 

I would have gotten back to you sooner but have been down with a intestional virus for over a week. lost 20+ #'s over this time!

Don

[72 LS5]

Don:

 

I hope you get well soon! All good points about the mags....

Ok, of course, the more we chat the more questions I have.

With the 560hp buildup you did (earlier in the post), would the air-gap RPM give better average hp throughout the rev band than the Victor Jr? I would sacrifice some peak numbers for some strong low-mid torque.

 

One more: I have two carbs in stock, an 800dp and 850dp - do you think this engine would benefit from the 850? Both are dog-leg style.

 

Thanks

[Guest]

P.S. look at Heckeng and several others with the 454ho crate engines with the 325cc rec port heads. They aren't bogging or laging. You think that GM put them heads on for looks? You know that if they had a oval port heads capable of the same overall performance they would use it wouldn't they. Brodix stopped making the small oval port head, Dart only makes a 370 cc runner oval head. The old timers still hold to the theory ovals are best on the street and guys that are affraid to go rec due to the advise of some old timers. If you have ovals and they due what you want then run with it! If you have factory ovals and you think you are going from street cruiser to bruiser by upgrading to a aluminum head only slightly better then your wrong.

Don

[Guest]

No the air gap DP wouldn't work better. The 800 would be the first choice. You know I hear that question all the time, A few years back a Mag had some test done by an independent outfit testing this theory, I happen to know the guy's that did the testing. I trust them even spoke to them after the article came out and was given the same info. On the dyno it appeared that the DP's were better, but it the car at the track the vic jr was always quicker and faster! This means more useable torque"quicker" and horsepower"faster".

Don

[72 LS5]

Don, you mention track times with the Vic Jr are faster but are these cars running crazy stalls and wild gears? I plan on running 95% of the time on the street with a 2400 converter and 3.31s. I would have thought the air gap would be a perfect choice, whereas the Vic Jr would be the choice for racing.

[monte70car]

don i got a question on a intake i have a 402 bored .40 over stock my current intake had to be shave the thickness of a stock intake gasket. im lookin at the accel pro ram intake ACC-74202E any idea on how well it will work on a mild street motor.the current intake is a edelbrock dual plane with a q-jet on it.

[Guest]

72 it's not a matter of street/race it's a matter of effeicency. How clean you get the air in and out. The combo's in the tests were a 406ci sb and 408ci bb, both were run with the ag dp and victor jr. It was supposed to one of the BB vs SB deals but it turned out to be that +. You see the SB with the vic jr beat the bb with the dp! It was a long drawn out process as the same car was used and all times were 3 run averages to eliminate single run variables. I remember the car to a street driven 73 camaro, 3.08 rear gear a B&M th350 with 2200/2400 converter. The dual plane in a performance app creates the same shear turbulance above 4800/5000 on most combos and limits power. As you may have picked up on, I am not a big EDDY fan! I like some of their manifolds but thats it! ALL of the heads I have seen from them are bad flawed castings. The potential is not as claimed. The only exception are the chapman,glidden,musi designed heads. They offer nothing for the cost to me. I know I've seen the commercial's "Made right, here in the USA". Ford also had the "better idea"!!!! I go by what I have seen work with my own eyes!! Back in 96 I did a 408 bb for a buddy of mine that ran 10.30's on pump gas in a stock suspension El Camino with 4.10 gears and a 2800/3000 stall. It was a high mantaince solid roller motor, had to lash those valves twice a month! Point is I see you paying good money for heads and stuff that read about in the mag's when you can get more for your money elsewhere! A friend of mine in marketing told me once,"The companies that pound the advertising drum the most are selling the least, thats why they advertise!" If you are selling 100% or near that level of your production then you don't need to advertise! The big E is all over the place with adds and mag articles, etc etc. Just like motor oils Valvoline is the cleanest probably the best crude based oil on the market and I see way more Quaker state and penzoil comercials than valvoline.

Don