alright. this might get me shot but i think it could be a nice idea if it is possible...does anyone make a hemi head for a 350?...i know they arnt chevy stuff...but is it possible to adapt them to work for a 350?...if its even possible other then cost and maybe the pain to get them running at first is there any downside?
thanks for help. i did a search but it came up rather dead
Snuffit

 

I see somebody else watched this weeks Trucks on tnn.

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late model 91 rs
fully loaded t-tops, red leather
paint- gm red and yellow blend (light red)
custom painted 16" Camaro rims
305 tbi 14"x3" O.E, hypertech chip, accel super stock plug wires
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tnn. sorry i cant get that channel (antenna only at this box of a house) this subject came about when a friend and i were arguing over how to make the most power in a 88gta and another friend said something about his dads car (early cuda) so we looked up the heads to see if anything was possible. hmm does that show have a site? we could have over looked something
Snuffit

 

www.truckstv.com

they didn't put the hemi heads on a chevy or anything (dang it), but they did talk about why the hemi head is so great, very interesting.

------------------
late model 91 rs
fully loaded t-tops, red leather
paint- gm red and yellow blend (light red)
custom painted 16" Camaro rims
305 tbi 14"x3" O.E, hypertech chip, accel super stock plug wires
hollowed cat, Edelbrock 3" cat-back
MTX sub and amp, Bose all around
vic_v8@yahoo.com
street kills: a lot of "family" cars, pickups, New v-6 stang, totally killed '86 SC Camaro, 91 z 28 with 305
next month: rest of ultimate tbi

 

I saw that truck show on TNN where they used the Hemi head. They explained what a hemi head was and named many good sides and no down sides. It seemed that a hemi head is far and away better than a normal style head. But then again, I'd be willing to be they full endorse everything they use on their shows, regardless of downsides.

I dont know if they can be used on an SBC.... I know Hemi heads are Mopar, so I have no idea.

------------------
1989 Chevrolet Camaro IROC-Z
L98 - 350c.i. TPI, rebuilt 700R4 auto w/shift kit, Dual catalyst Monza PaceSetter Cat-Back, SLP 1 5/8 Coated Headers, 3.23 Posi rear, Hypertech chip with 160stat, MSD 6A, Under-Drive pulleys, AFPR, K&N's, !Air Box w/ Ram Air, moddified MAF, !TB Coolant, Spohn Dual Cat SubFrame Connectors, Alarm, Keyless entry, remote starter, 92 Z28 AeroWing, Brand New Paint (6/21/01)

Future: ZZ4 TPI w/EGR, T56, 3.42 or 3.73, Spohn strut tower brace and LCA's

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2.8 MPFI, no mods
225,000 miles and still ticking!

More info and pics on my webpage:http://go.to/iroc-z

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well im almost glad i didnt see that show, if its as useless as the site i would have been confused. anyway back to the first topic...i found a tpi setup for these heads...but i have no idea if there is a way to slap them on a nice 350...anyway even if they could go on...is there any major gains to be expected by them?
Snuffit

 

Big blocks have had semi-hemispherical chambers and valve arrangements since 1965. Those seem to work pretty well.

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Later,
Vader
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Justice and Freedom will Prevail

 

Hey Vader you sound like you know what your talking about....is it possible to get big block heads like that on a 350?.or normal 350 head like that..and even if it is can i get strong enough ones to hook up a twin turbo setup?
Snuffit

 

Snuf,

Anything is possible, if you throw enough money at it. Changing BBC heads to SBC block patterns wouldn't be prudent. The bore centers are way different. The chambers on BBC heads are often way over 100cc, and the water jackets and bolt patterns aren't even close.

But I suppose if you really wanted to, you could weld head bolt sleeves through the water jackets, relocate the water passages in the case, cut the heads and reweld them to shorter centers, and machine the whole mess when you were finished. You might be better off trying to build new heads from plate steel or just filling the chambers on a bare casting and machining semi-hemi valves into SBC heads.

It would probably be far easier to shoehorn a 520 Ramjet into the fenders than to reinvent the wheel. 510 ponies with 550 ft/lbs and a new pair of front springs would be pretty wicked in a ThirdGen.

If you just want decent head flow on your SBC (which is what the hemi chanbers are supposed to promote) you might want to look at Pro Action heads that outflow many BBC and Mopar hemi heads.

------------------
Later,
Vader
------------------
Justice and Freedom will Prevail

 

To my knowledge nobody has produced a SBC hemi head. That's not saying it hasn't been done. I've seen dual overhead cam heads for the SBC. It's just that if it has been done the cost doesn't justify the advantages.

Although BBC heads are not true "hemi" there is one BBC head that is. www.feuling.com makes a BBC hemi head. Their home page really sucks now but they used to have some good stuff on display about their BBC heads.

Many makes and models have used hemi heads over the years. Ford Boss 429, Harley Davidson Shovelhead engines, many import engines.

Although the design will produce more power, the shape of the combustion chamber doesn't promote good flame travel. In an age of more fuel efficient and less polluting engines, the hemi design isn't what the manufactuers are looking for. The common wedge shaped combustion chamber seems to be the best shape to use now.

We could always go back to the old flatheads where the combustion chamber wasn't even part or the cylinder.

------------------
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Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

I've heard that NASCAR engines have almost no chamber in the head, and they use a dished piston to make the shape on the chamber. That way, you could change the shape of your combustion chamber by just changing pistons. Also, I work at a Caterpillar factory where they make medium duty truck engines, and they have no chamber volume in the head at all. It's all made up in the piston. They have a lot of the same features used in race blocks in the name of durability.

Please don't bash me too bad for bringing up diesels. I just thought I'd mention it.

------------------
Jeff

'85 Berlinetta, Special Beater Edition
Mods include a 4bolt 350 with 280*, .460 lift cam, Vortec heads, Comp Cams roller tip rockers, Edelbrock TES headers, no other exhaust . Also, rusted parts on all 4 corners, and crumpled fenders, thanks to the previous owner.

 

I seem to recall a company named 'dominion' who made hemi heads for the SBC. Not only were they hemi heads, but had 4 valves per cylinder, and they used special valve covers and some kinda goofy pushrod splitter to work 2 valves... I remember reading up on them in a perf mag... maybe super chevy or chevy high performance about a year ago... Haven't heard anything about them since though. I think they retailed around $3200 a pair with the valve covers. I was heavily intrigued by them and read the article probably 50 times or so...

 

i remember that too and i HAVE IT somewhere.....i almost never throw out my mags

from what i remember though.....like stephen

cost didn't justify the means

 

Searches would lead one to believe the company went out of business. Here's a bit of info on the Dominion heads tho for anyone who's interested anyways.

http://www.deadbird.org/z/32vh1.jpg
http://www.deadbird.org/z/32vh2.jpg
http://www.deadbird.org/z/32vh3.jpg
http://www.deadbird.org/z/32vh4.jpg

I won't be responsible for blindenss from trying to read all of that
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[This message has been edited by deadbird (edited September 24, 2001).]

 

That looks more like a pentaroof than a hemi.

 

Arias makes Hemi Heads for big chevies.Strictly race stuff,though.A lot of Drag Boat racers use the Arias 557 which is an aluminum aftermarket big chevy type block with hemi heads.Only saw one on the street once, and it was in a '69 Camaro Pro Street Car (blown and injected).

 

A company called Aaro makes some 4 valve hemi heads similar to the Domimions mentioned above. They use a stock intake and exhaust.

 

Chevrolet was very close to producing Hemi heads for the small block in 1963 for the lightwieght Grand Sport Corvette. Not only were they Hemi, but they were also dual-plug. GM Killed it, along with the Mark II big block, with their racing ban.

In the book, "Corvette, America's Star Spangled Sports Car", by Karl Ludvingston, a picture of it appears on page 173.

Too bad!

 

Tom, do you happen to know anything about this company? i think these heads could make one great 350 if the rest was around to match it...thanks
Snuffit

 

I don't really know much about the company. I read an article about these heads years ago. I would do a search on the net and see what you come up with. Here is a link that has pics of the heads -Scroll down 7 pictures (about 1/4 of the page). It states that the heads pictured are for BBC but are available for SBC too. Not true. Look at the pic at the exhaust ports...SBC.

http://members.tripod.com/lyc_42/chevy/sb/sb.htm

 

Just found it. Here is the link:

http://www.araoengineering.com/

 

I saw this weeks Trucks too on TNN and hemi heads do seem alot smarter if you look at the math behind them. Why aren't all heads like this?? LEt me know if its do able.

 

Score on for my memory...

I used to have an old rag (might have been super chevy, but could have been any of 'em) where they uncovered a very rare find. Basically while walking through the aisles at a show they found a 69 Z28 with what looked like big block heads on a small block. They got intrigued and went about tracking down their history.

As it turns out they were an original chevy casting from the late 60s, maybe 100 or so were cast. A lot of them ended up in smokey yunich's garage. They went right to the source to get the scoop. Smokey remembered the heads (btw, they were based off the BBC design), and he remembered why they never took off. While they had a great intake port, the exhaust port was serverly compromised. Thus, it took him massive amounts of reworking to make them make the same power he was getting from conventional race SBC heads, and thus weren't worth it and the project died.
I wish i still had that issue, it was a weird looking set-up for sure. Anyhow, thats your trivia for the day.

An important thing to remember about those fancy 4 valve heads...you ever hear anyone win anything with 'em. Besides the gee whiz factor of being different, apparently you can still do whatever you want with regular old SBC design heads. If the 4 valve heads were so good, someone would run 'em, even if they are 3-4k a set...again, you ever see a set installed on anything?

 

In response to Ed's point, a head like that will put a car into some class that's so far removed from anything stock or street, that the odds of finding it in any kind of sanctioned racing are somewhere between slim and none. And, in any of the sanctioned classes where there's (a) enough prize money to support that level of cost and (b) rules that would allow such a thing, one of 2 things will happen. Either someone will slap a set on and win everything and they'ld get banned; or they the same thing would happen and they wouldn't get banned, in which case everybody in that class would be running them within one season.

Still, they might be fun for an unlimited-budget bracket racer / Saturday night special... with the emphasis on "unlimited budget"...

I dimly recall a prototype porcupine-head design for the small block too, might be that same one Ed is thinking about. The problem was (as usual) the head bolts. SBCs have too many of them, and it's pretty hard to work the ports around them.

------------------
"So many Mustangs, so little time..."
ICON Motorsports

 

Thems the ones RB, smokey dubbed them the 'porcupine' head cuz they just had too many problems to be worth using. That definitely clicks. IIRC whatever rag it was had a picture of the yellow 69 Z28 on the cover of it, and was probably back in 95-96 timeframe if any of you have a bunch of back issues from around then and you want to look for it.

 

Most of us drive street cars. I race in local friday night eliminations, and there are no such classes. I also race solo 2 auto cross. A mod like those heads surely would put me in some prepared class, but so does the 400 CID engine I already installed. My point is that these heads could make a sick street car. look at the flow #'s at .300" valve lift! They put TFS, AFR, Canfields, Bla,bla,bla to shame. The only SBC heads I've seen that come close to these as far as flow are the Pro Action 14* heads -and those aren't street heads.
...Or someone that wants a sweet N/A street car. If I had the dough, I'd try them.

 

Here are three pics of the "porcupine" smallblock 302 heads. They were intended to run against the Boss 302 Mustangs in Trans-Am racing.

<img src=http://albums.photopoint.com/j/View?u=562286&a=13758919&p=54522209&Sequence=0>

<img src=http://albums.photopoint.com/j/View?u=562286&a=13758919&p=54522216&Sequence=0>

<img src=http://albums.photopoint.com/j/View?u=562286&a=13758919&p=54522477&Sequence=0>

 

And here's the '63 Grand Sport Corvette Hemi small block. In addition to the heads, it was also a 377 stroker. Too bad Chevrolet didn't produce 100 of these per the original plan!

<img src=http://albums.photopoint.com/j/View?u=562286&a=13758919&p=54522480&Sequence=0>

 

They said there was no disadvantage to Hemi heads? What about the valvetrain? What about price? The worlds fastest doorslammer is a third gen camaro with wedge heads.

 

Downside? Now that you mention it...

1. To get high compression with a hemi, you must have a big dome on the piston. This means heavier pistons and hot spots.
With the newer wedge designs, you can use a flat or dished piston and still get upwards of 13.0:1.

2. IIRC Ford quit using their hemi heads in Pro Stock since higher lift and duration are limited by the geometry of the head and valvetrain. The intake and exhaust valves were getting closer to colliding with advancing cam technology.

3. There's nothing new under the sun with hemi heads. They've been used in engines since the 1920s.

4. A hemi is a hemi. A wedge can take on all sorts of shapes and sizes.

Since Mopar is back to using Hemis in Pro Stock, we'll see if the hi-tech wedges have surpassed them or not. But years ago, the hemi design was the most effective way to make power.

 

Man, those pics are MIND BLOWING! Having pwersonally worked on at least half of all the Small Block Chevys ever produced (kidding) those heads/engine just look WRONG. You never realize how "normal" looking siamesed center eshaust ports are until you see a SBC without them.

I mean, even Chevy's full-race "mirror port" NASCAR heads STILL have siamesed center exhaust ports! There's something very EVIL and very FORD looking about it!

 

Ed:

I'm not talking about some magazine article... I was referring to the real thing, at the time.

We don't need no steeeenkming magazine articles

------------------
"So many Mustangs, so little time..."
ICON Motorsports