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  #1  
Old 01-07-2008, 10:02 PM
OHD OHD is offline
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Default Hemi engines, questions and related topics

Ask or post any Chrysler type Hemi engine related question here from 331 to Blown nitro engines and I will either answer it or get the answer for you from my circle of contacts from the last 45 years..... I do not or never have done much with the little old Dodges or Desoto engines but can send you to people who have done them also..

I currently am building 3 more big inch 426 style engines and have current info on what is hot and what is not...both from the manufacturers and the end users.

I will refrain from posting in the rest of this forum and stay in my zone of most expirence and keep it on performance related topics.

You want to Hemis do it here.....
  #2  
Old 01-07-2008, 10:07 PM
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I have questions on the old HEMI's. Not seeing them around these parts, junk meatl gets someone paid and nothing lasts around here, I got a bit confused on swapable parts from the HEMI and POLY heads. Ummm, I think it was the 345 came in 2 versions back in the day. 331 could use bigger dispalcement parts like heads?

Could you clear some of that up?
I'd hate to say what I know, becasue it's really nothing on this topic, but it's all scrambled up there.
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Old 01-08-2008, 12:37 AM
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Quote:
Originally Posted by rumblefish360 View Post
I have questions on the old HEMI's. Not seeing them around these parts, junk meatl gets someone paid and nothing lasts around here, I got a bit confused on swapable parts from the HEMI and POLY heads. Ummm, I think it was the 345 came in 2 versions back in the day. 331 could use bigger dispalcement parts like heads?

Could you clear some of that up?
I'd hate to say what I know, becasue it's really nothing on this topic, but it's all scrambled up there.
Hummmm.....
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Old 01-08-2008, 02:21 AM
DartGT66 DartGT66 is offline
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With all your experience, you should find a lot of company here: http://www.moparchat.com/forums/showthread.php?t=61961 this is the second try for the subject, I think the first one was about 1000 pages long.
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Old 01-08-2008, 08:59 AM
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There are no parts swapable between a Hemi head and a poly head.

Early Chrysler hemis were low deck 331 354 high deck 392
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Old 01-08-2008, 09:19 AM
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With all your experience, you should find a lot of company here: http://www.moparchat.com/forums/showthread.php?t=61961 this is the second try for the subject, I think the first one was about 1000 pages long.
Not everyone drag races a Hemi engined car, lots buy and modify for street use, to be cool, or longevity, as most 426 style engined cars were high maintenance, premeanent oil leaks, and bolt bucket money pits from the factory.

People, to this day, will restore one to that condition.

Mopars never were and are never going to be, premium well made cars. Just fast bolt buckets.

PLUS...some owners are much too cheap, when it comes to spending the bucks, to do things, so they will "shine" and last.
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Old 01-08-2008, 05:03 PM
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Here's one. Why do some people say the 3G Hemi is not really a hemi??
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Old 01-08-2008, 05:37 PM
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Because the combustion chamber is not hemispherical.
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Old 01-08-2008, 06:16 PM
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Why does Chrysler bill it as such. What ring of truth is there that they call it a "Hemi".
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Old 01-08-2008, 07:00 PM
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Never got a bill from Chrysler so I don't know. Call Celebrus management company to get your answer.
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Old 01-08-2008, 07:23 PM
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Quote:
Originally Posted by OHD View Post
Ask or post any Chrysler type Hemi engine related question here from 331 to Blown nitro engines and I will either answer it or get the answer for you from my circle of contacts from the last 45 years..... ..
Hmmmmmmnnn.......so much for one stop shopping!!!
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Old 01-08-2008, 07:53 PM
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Quote:
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Never got a bill from Chrysler so I don't know. Call Celebrus management company to get your answer.
Some Hemi expert you are.

Oh, Do you mean "Never got a check.... from Chrysler.."?
Jeezus Pete!!!
  #13  
Old 01-08-2008, 08:25 PM
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Strictly speaking, I believe OHD is correct when he says the current Hemi does not have a completely hemispherical chamber - however it's close enough and the principle is the same, and most important they call it a Hemi because they can!! They own the trademark. And that sells vehicles!!! Anyway, OHD, good to know you're willing to share since my next door neighbor has a 392 that he intends to stuff into his clean 82 D100 stepside. Should be a fun truck when it's done.
  #14  
Old 01-08-2008, 08:30 PM
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The 3G Hemi is the closest the engineers could get to a hemispherical chamber while still having good combustion efficiency for better power, mileage, and fuel economy. I like the new Hemi design much better than the older ones because the new one isn't dumping unburned gas out the tailpipe and still flows a TON better than comparative V8 heads from other companies, especially GM. Ford is "cheating" with 3- and 4-valve-per-cylinder heads so I'll leave them out of it.

If you look at a 3G Hemi combustion chamber it's basically a shallower version of the old "true" Hemi (for smaller combustion chamber volume, so they can use flat-top pistons and still have good compression) with two spark plugs, one on each side of the intake/exhaust valves (to speed up combustion and make it more complete), and with a good amount of squish area on the sides to improve turbulence and combustion efficiency even MORE. If any of you know Harley-Davidson motorcycles it's actually similar to the Buell-designed "bathtub"-style chambers now used on all Harley V-twins (apart from the VRSC), but with a little less squish area and with a shallower chamber and two spark plugs per chamber.
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Old 01-08-2008, 09:05 PM
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Thanks for the explanation guys. I saw some cnc'ed 6.1 Hemi heads at Southland Performance and they looked like the had hemispherical chambers to me. Just how "hemispherical"??? I guess not enough for traditionalists.
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Old 01-08-2008, 09:06 PM
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They still have sooo much power potential, I don't think they should be underestimated.
  #17  
Old 01-08-2008, 10:09 PM
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Quote:
Originally Posted by go-fish View Post
They still have sooo much power potential, I don't think they should be underestimated.
You couldn't be any more correct. It really pisses me off when so-called "car guys" say how the new Hemi is junk when we get on the topic of Hemis. They obviously lack the intelligence to understand exactly how they work, and they compare the stock 5.7L pickup truck engine to the 'caged animal' 426 Street Hemi and say it's nowhere near as powerful. I'd prefer a hot-rodded 3G Hemi over a 2G in a performance car any day. Now for pure bad-assness, all-aluminum 528 dual-quad tunnel-rammed Hemi is the way to go.
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Old 01-08-2008, 10:26 PM
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I would rather have a 392" TT 3G anyday... and spend half as much. I think that's the way to go.
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Old 01-08-2008, 11:42 PM
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All...Good points.....I like them all.......All just depends on what your building....
I havent got to build any of the new style yet....
  #20  
Old 01-08-2008, 11:53 PM
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Just wait a couple years. Given time, the 3G Hemi will be treated similar to the GM LS engines and Ford Modulars. Except, they'll realize how superior Chrysler engineering is .
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Old 01-09-2008, 01:09 AM
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"all-aluminum 528 dual-quad tunnel-rammed Hemi is the way to go."

We like them larger (572 to 600+ inches) at 2 plus hp per inch on straight pump gas.

The size limitations of the new 3rd gen semi hemis will limit their potential. Plus good internal parts are not being made to handle outlandish power levels.

3rd gen hemis power is nowhere near their old foes, in the LS7 small block Chevy yet... (simular to orig 426 vrs L88 or the ZL1)... and probably never will be.

When a 3rd gen semi in a 3200 lb car gets in low to mid 8s in the 1/4, I might look at them..otherwise I will stick with tried and true old 426 style stuff...
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Old 01-09-2008, 01:18 AM
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Gofish when you get one and do your performance build up. Let everyone know what it does and how much you saved.

I am sure that will be interesting.
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Old 01-09-2008, 02:25 AM
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I still think you should share your expertize in the other topic I linked earlier, those guys could learn a lot from you.
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Old 01-09-2008, 10:04 AM
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I still think you should share your expertize in the other topic I linked earlier, those guys could learn a lot from you.
Now they know exactly where to get it, IF they want another source.
  #25  
Old 01-09-2008, 01:20 PM
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Quote:
Originally Posted by OHD View Post
Gofish when you get one and do your performance build up. Let everyone know what it does and how much you saved.

I am sure that will be interesting.
I don't know if it will be anytime soon. You see I just put together a 650 HP LA that will suffice for awhile. It's all roller and blown using a small cam so it'll be lasting awhile.
I could have bought a crate 426 Hemi for the money but I was more interested in performance.
The 2G Hemi's sure are interesting though.
  #26  
Old 01-09-2008, 07:13 PM
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Isn't MP starting to come out with more hot-rod bottom-end parts? I believe the new 392's have a strengthened block (siamese'd too), and the aftermarket is starting to make things like crankshafts and pistons and rods. Of course it's still a new engine, so you can't build a giant-inch race engine with 3G architecture, but it is a much better choice for street/strip cars compared to 2G Hemis or even LA small-blocks. Remember also the 3G is a small-block, so I doubt there will ever be one that has over ~450 c.i. 2G is still the best for all-out drag racing.
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Old 01-09-2008, 09:09 PM
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Mopekid please tell us what cars or vechicles you have had with a 331,354,392 or 426 hemi, that you base your OPINION upon.

Compare and contrast the aspects of the vechicles so everyone gets a clear understanding of your expirences.
  #28  
Old 01-09-2008, 10:00 PM
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What? I'm not disagreeing with anything you've said. All I'm saying is that the 3G Hemi is a more efficient and street-friendly design than the 2G, but lacks the serious racing background and design of the 2G, which makes the 2G better for all-out racing. I'm just trying to explain why it's a better idea for people to use the 3G Hemi in more street-oriented cars than 2G Hemis because they are lighter and more efficient.

I do openly admit I have NO experience with Hemis. And because I am only 16 and have never even driven a true performance classic Mopar, and I don't have the money to do so now anyway, I try to read as much as I can and learn as much as I can about these cars and the engines used in them. It's a proven fact that a lighter, more efficient engine is better than a heavy (relatively) inefficient one until you actually need the bigger, heavier engine's extra strength and displacement potential. I'm sorry I said anything; I was just trying to add what I knew.
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Old 01-09-2008, 10:47 PM
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Hey Mope,
I wouldn't worry too much about it, Old HD probably hasn't had his prune juice today and he's still a little bit bound up and it's making him slightly irritable.........Posers get like that sometime................
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Old 01-09-2008, 11:43 PM
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All right, thanks 23T. I really try not to sound like I know everything, I know how annoying that can be. I just wanted to add some of my knowledge to the discussion, not convince everyone that I am right and no one else is.
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