Jump to content

"hemi" heads?

chevy38fan

Recommended Posts

chevy38fan Enthusiast

chevy38fan

Posted
Posted

There's a debate on one of the dodge forums as to wether or not most modern day engines use hemispherical heads or not. I know some are somewhat hemispherically shaped, but others are still wedge shaped..

 

So my question is, does GM use hemispherical heads on their 4.8, 5.3, 6.0, and 8.1 Gas motors?

what about the LS1/LS6 motors?

Rotorwrench Enthusiast

Rotorwrench

Posted
Posted

Nope, they are all wedge shaped. On a true hemisherical head the spark plug goes through the valve cover into the cylinder head with a valve on each side. The valves are not in a straight row front to back. Intake valves are on the intake side of the head and exhaust vavles are on the exhaust side.

01Burb Enthusiast

01Burb

Posted
Posted

Yes. A DOHC engine by design, has it's valves on 'opposite' sides of the chamber with the plug (or plugs) in the middle.

speedshifter Enthusiast

speedshifter

Posted
Posted

This is true, i was just reading what Rotorwrench posted about what charachteristics a hemi has, and the Northstar popped in my mind and fits those requirements. Working on Northstars all the caddy dealer, they just seem to be a familiar motor to me.

 

Isn't also true that all the Mopar Hemi's are pushrod motors? Or is the new one OHC?

  • 3 months later...
tjl5709 Enthusiast

tjl5709

Posted
Posted

The 5.7L HEMI is indeed a push rod motor.

 

This was observed at their NAIAS display.

bigdogs Senior Enthusiast

bigdogs

Posted
Posted

I remember reading awhile ago that GM also made a hemi head back in the 60's (if I remember correctly even before Chrysler) but it was just a prototype and never made it into production as they thought it was too expensive.

Tucson_02Silverado Senior Enthusiast

Tucson_02Silverado

Posted
Posted

Diamler is confusing everyone with "HEMI" and just using the word "HEMI" to describe their new 5.7L engine.

 

Mopar "HEMI" heritage started (someone correct me if wrong, I'm not a Mopar historian) in the late 50's with the Chrysler 300 as a 392CI using hemispherical heads. The current floating lore of the "HEMI" is thought of as the late 60's 426CI as used in NASCAR, SuperBird-DaytonaCharger.

 

Diamler ads never say 5.7L "HEMI", just "HEMI" and will show a 5.7L intake cover as a way to avoid someone legally demanding a 426CI in their truck instead of a 357CI. Had Diamler been smarter they should have just call'd them Powered by Magnum 357 as a reverse word play on the handgun cartridge.

Shark Bait Enthusiast

Shark Bait

Posted
Posted

:P Tuscon 02Silverado Not to quibble but the Chrysler "Hemi" thing started back in about 1953 with the original 331 CI used in Chyslers, Dodges, etc. It then went to 354 ci (just an overbored 331) in the late 50s, then to 392ci and finally 426ci.

 

You are correct in that when people think of a "Hemi" they are most likely thinking of the 392 and/or 426 versions. The old 331 was a "Hemi" but it weighted a ton and produced very little power unless highly modified.

 

Not being a Chyrsler lover I have no information about the new 5.7 "Hemi" configuration. I will bet however that the 8.1 Vortec heads are as good if not better than the Chrysler 5.7 "Hemi" heads. Seems to me Chrysler is just trying to get a lot of advertising mileage from the old "Hemi Ledgend". A friend had a 1965 or 66 "Street Hemi" and it was one bad car right off of the assembly line. The "Old 426 Hemis" were very, very strong!!!!

 

A long time ago I took a 331 Hemi, bored it to 354, put lots of carbs (6X 2bbls) and internal parts in it, coupled it to an early 50s Cad-Lassall 3 speed manual transmission and an Oldsmobile rear end and stuffed the whole mess into a 1953 Studebaker. Was kinda a neat streed/drag car - but very, very crude by todays standards. :thumbs:

  • 2 weeks later...
C1500 Enthusiast

C1500

Posted
Posted
Diamler is confusing everyone with "HEMI" and just using the word "HEMI" to describe their new 5.7L engine.

 

Diamler ads never say 5.7L "HEMI", just "HEMI" and will show a 5.7L intake cover as a way to avoid someone legally demanding a 426CI in their truck instead of a 357CI.  Had Diamler been smarter they should have just call'd them Powered by Magnum 357 as a reverse word play on the handgun cartridge.

Go to the Dodge website and you will see the engine specified as "5.7 Liter Hemi"

  • 4 months later...
Hemi_#1 New Member

Hemi_#1

Posted
Posted

First of all you guys clearly have no idea what you are talking about because chev was rated the worst truck of the year. they are lacking in power, ground clearance and there down right good for nothing. And i saw someone advertising that they had a 98 chev with a 4.3L o no stand back he might run me over. HAHAHAHA! You guys should get your thumb out of your but and get a real truck. A hemi :puke:

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.3k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,732
    Total Members
    8,960
    Most Online
    user087
    Newest Member
    user087
    Joined

  • Who's Online   3 Members, 0 Anonymous, 885 Guests (See full list)

  • Latest Articles

  • Posts

    • Grumpy Bear
      OCI, not when but why?

      By Grumpy Bear · Posted

      Here's a starter kit:    CC Jensen, a Danish oil testing Concern gives us the following guidelines:   ISO 14/12/10 Very Clean Oil ISO 16/14/11 Clean Oil ISO 17/15/12 Lightly Contaminated ISO 19/17/14 New Oil ISO 22/20/17 Very Contaminated and not suitable for any service.   In addition CC Jensen gives a table showing how engine life is increased by cleaning up the oil. For example cleaning the oil from 19/17/14 to 13/11/8 will extend motor life by a factor of 6X.   But even cleaning it two “Life Extension Classes” will double motor life. So perhaps giving those classes would be useful:   21/19/16 20/18/15 19/17/14 18/16/13 17/15/12 16/14/11 15/13/10 14/12/9 13/11/8   *************************************   https://testoil.com/program-management/setting-iso-cleanliness-targets/   Third paragraph from the bottom will give a starting point.    Your next question should be, okay 10um at what Beta ratio and the answer is in the graph Beta 75.   Then the next question is what is your chosen filters profile? (Purolator PL series below) The red dot is Beta 75. This was the information I obtained from MANN a few years ago. So the best filters, Purolator One, AMSOIL EA, FRAM Ultra, Royal Purple, Bosch Premium should get a doubling engine life over filters like Purolator L, any service filter from any quick lube, WIX, NAPA, STP, Mobil 1, Purolator BOSS.    And as noted by CC Jensen a 2-5 micron @ Beta 200 bypass system has the capability of a six fold improvement. AMSOIL has such a system as does Donaldson.       Now having said all that testing is the touchstone. Test the oil NEW and test it with your chosen filter. Then test over milage. Do the work, get the result. But understand this in NOT absolute BECAUSE this is one factor in isolation.   Example:    A valve spring supplier can state that with cam X and a valve train of Y grams the valves will not float to 7K rpm. is that true if the builder choose a system 20 grams over limit? Common sense must be used and limits understood. 
    • bruceb58
      Road Master Active Suspension

      By bruceb58 · Posted

      This doesn't look like a GM truck. Not needed on a HD truck
    • CamGTP
      Gas Prices

      By CamGTP · Posted

      It varies a ton around me. Some places are still at $5.00 or higher and others are way down into the $4's.   Offroad diesel was $4.02 at the one station I passed today.
    • Hdwrguy
      2027 Chevrolet Silverado: Official Discussion

      By Hdwrguy · Posted

      So after reading the reveal from Chevrolet, I kept asking myself...why did the trim levels change?   Here are the official ones:   Work Truck (WT): The quintessential fleet truck, built with durable, easy-to-clean interiors for commercial or utilitarian use. Custom: A stylish, road-oriented trim that adds a more refined appearance, standard dual exhaust, and modern exterior styling. Custom Trail Boss: An entry-level off-roader featuring a 2-inch factory suspension lift and 34-inch mud-terrain tires on a budget. Silverado: Serving as the new base consumer truck (replacing the previous LT trim), it comes standard with the Z71 off-road package when equipped with 4WD. Trail Boss: Steps up the off-road hardware with the 2-inch lift, 34-inch tires, monotube shocks, an exclusive off-road hood, and more premium interior options. ZR2: The flagship off-roader. It boasts 35-inch mud-terrain tires, Multimatic DSSV dampers, front and rear electronic lockers, forged carbon-fiber interior accents, and an available hardcore Bison Edition (co-developed with AEV). High Country: The pinnacle of luxury. It replaces bright chrome with modern satin chrome, 22-inch wheels, premium leather, real wood interior trim, a panoramic sunroof, and an exclusive front-passenger touchscreen. As others have stated, why would you want a Silverado - 'Silverado' - wth?? LT needs to remain!!!   Also, there will no longer be a dedicated Z71 model.  All 4x4 trucks will have the Z71 package. Carplay is also something that cannot be removed.  Hopefully it will remain.     I am excited about the 5.7L V8 (350 C.I.D.)  Old school Chevy power.  My only concern is whatever version of AFM/DFM cylinder deactivation.  Too bad that isn't an option a buyer can choose to have or not.   I will definitely be stopping by my local dealership when these trucks start showing up.
    • richard wysong
      Gas Prices

      By richard wysong · Posted

      I haven't seen diesel for less than $5.30 anywhere in my area

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...