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Discussion Starter #1
Hi yall just wanted to get a straight answer from knowledgable people that isnt biased like everywhere else. Obviously the Hemi port setup is nice and flows well but what about the combustion chamber? It works well in top fuel but is a hemi chamber the optimum for N/A and boosted gas/methanol setups?

Thanks for any/all replies.
 

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A true hemi is only worth a damn if its blown or on fuel.

If you need more than 9:1 static with a hemi... Id put money on the wedge making more power.
 

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Hemis are flow queens on the bench, but when you stuff that big dome in the chamber the flame front has a hard way to go. The centered plug is great but can be achieved with something like the drce stuff and have a lot flatter chamber with less surface.
 

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Discussion Starter #6
Thats what Ive thought for a while now too. Not really a semi-hemi but bigger than regular valve bowls.
 

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Discussion Starter #7
A true hemi is only worth a damn if its blown or on fuel.

If you need more than 9:1 static with a hemi... Id put money on the wedge making more power.
Care to elaborate on this? What do you mean with the second line?
 

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Care to elaborate on this? What do you mean with the second line?
Read the post Old Rusty made and think about what you would have to do to achieve more than 9:1 static in a hemi. Think about how much dome it would take.
 

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I have a set of the new generation IHRA Ford hemi heads that have the small 64cc wedge style chambers, would chamber softening mods work better than a dished piston on a naturally aspirated motor ?
 

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I spose it would depend on what you wanted to do. Goal? Expectations? Which wedge head? Big Block? RPM, Victor, -1, SR, EZ, 572, 600, B1...
Michael
 

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Discussion Starter #13
Ive heard that Hemi heads dont induce swirl very well and also have no quench. This maybe a dumb question but what exactly is swirl and what does it do? Is it exactly what it sounds like? The a/f charge swirling? And what is quench/whats the benefit? Also, with port velocity, I was reading that having supersonic exhaust flow is much preferred? Icant remember his name but he was an old school pro stock engine builder and said he would build the engine to barely make any low-lift flow - cant remember his reason why. Anyway, if supersonic exhaust flow is good, would supersonic intake flow not be good as well? Obviously you dont want ports to be too small ....
 

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hemi heads like big cid. if you where building a 600cid+ i'm using hemi heads. even the pso heads have a hard time with hi rpm and big cid...
 

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Im a wedge guy. I have had the tradional 426style Hemi's in the past. They have a number of drawbacks I do not care for. Piston weight being way up that list and cost per HP being the other. I now have a wedge in my car, makes more power for less money than the Hemi was. Not to mention the wedge is less weight. FWIW my wedge deal makes 1050hp for the same money as a 900hp Hemi was.

Oh yeah I also have one of those Hemi's that Curtis listed. It certainly makes power but Hemi, come on.....

 

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on gasoline..all the points mentioned are giant / large factors...and well agreed upon



but in a forced induction nitro or methanol blower type setup..oftentimes the traditional hemi setup with the valves in direct shot straight out to the port is able to cool the chamber better when during overlap without disturbing flow....no cross chamber movement...

but it is well understood when running on gasoline,...you need that purposefull disruption of a cross movement in flow to help mix it all up...
 

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Hi yall just wanted to get a straight answer from knowledgable people that isnt biased like everywhere else. Obviously the Hemi port setup is nice and flows well but what about the combustion chamber? It works well in top fuel but is a hemi chamber the optimum for N/A and boosted gas/methanol setups?

Thanks for any/all replies.
I will have to be the one to give you a straight answer because surely no one else will.

I see you have noticed the 426 Hemi does well in top fuel. It has won almost every single AA/TF and AA/FC race in the last 48 years.

You wondered about N/A.

Well, in Pro Stock it kicked everybodys ass so bad they had to give weight breaks to all the other cars because nobody could keep up.

Boosted gasoline is not a popular class but it has done well, and boosted methanol, well I think you will see quite a few Top Alcohol dragsters and funnys cars with hemis.

Is the chamber optimum? I don't think so. We have had nearly 50 years to come up with a better one and it appears that by bringing the sides in a little to reduce chamber size and piston dome (as seen in the current Dodge pro stock hemi and in the Sonny's hemi) that it works a litttle better.

Basically nobody has came out with much of a better head for the 426 hemi in the last 48 years. We are having to use what is basically a stock head. After 50 years of constant development the wedge head (which has nothing in common with a wedge head, it is all a custom made pro stock head) will make more power than a stock 426 hemi head.

Hemi vs Wedge? Which one is better today? Personal preference I guess. If you offered me a wedge for free I would go the the bank and borrow the money for a hemi. I just like 'em.
 

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Read the post Old Rusty made and think about what you would have to do to achieve more than 9:1 static in a hemi. Think about how much dome it would take.
insert a 5inch stroke, problem solved :rolleyes:
 

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Discussion Starter #19 (Edited)
I will have to be the one to give you a straight answer because surely no one else will.

I see you have noticed the 426 Hemi does well in top fuel. It has won almost every single AA/TF and AA/FC race in the last 48 years.

You wondered about N/A.

Well, in Pro Stock it kicked everybodys ass so bad they had to give weight breaks to all the other cars because nobody could keep up.

Boosted gasoline is not a popular class but it has done well, and boosted methanol, well I think you will see quite a few Top Alcohol dragsters and funnys cars with hemis.

Is the chamber optimum? I don't think so. We have had nearly 50 years to come up with a better one and it appears that by bringing the sides in a little to reduce chamber size and piston dome (as seen in the current Dodge pro stock hemi and in the Sonny's hemi) that it works a litttle better.

Basically nobody has came out with much of a better head for the 426 hemi in the last 48 years. We are having to use what is basically a stock head. After 50 years of constant development the wedge head (which has nothing in common with a wedge head, it is all a custom made pro stock head) will make more power than a stock 426 hemi head.

Hemi vs Wedge? Which one is better today? Personal preference I guess. If you offered me a wedge for free I would go the the bank and borrow the money for a hemi. I just like 'em.

Yeah the BAE Hemis seem to be the most dominant thing out there in Pro Mod/Top Alc/Top Fuel along with the AJPE Hemis to a lesser extent.

Thanks thats what I figured. As far as the valve location and how direct the ports are, do yall think theyre too direct? I heard before that with the ports that straight/direct in an N/A setup it actually makes the burn biased to one side of the chamber?

But yeah I like Hemis too even though Im not the type that could afford one lol.

Also, kinda off topic, but do yall think SOHC/DOHC would offer many advantages in a drag race setup with Hemi or Wedge heads? Obviously they have good valvetrain stability but other than that, is there any real straight-up power advantage?
 

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Hemi vs Wedge? Which one is better today? Personal preference I guess. If you offered me a wedge for free I would go the the bank and borrow the money for a hemi. I just like 'em.

Ray Barton told me wedges were for busses and trucks :p
 
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