HEMI -the real 426- vs LT4
 

I just caught the last part of the segment on Dream Car Garage at 8:15 where they put a HEMI Challenger on the dyno for "Dyno - Truth or Dare". (I might not have gotten all of that last exactly right, maybe a Cuda)

This car with the original 426 hemi advertised at 425 HP back then laid down 314 rwhp???? Sheet, the average LT4 in stock trim matches that! My Heads/Cam LT1 with the original cast iron manifold and restrictive exhaust laid down 311 rwhp.

What was so great about those hemis that they are worth $500K at BJ and all the rants from the Speed Channel crew?? Now in race trim those engines make massive power, but the street car, the few that were ever sold, aren't all that great. Our C4s match or beat them. And that's the original Nascar hemi, not the phony engine that marketing is pushing so successfully today.

:lurk:

Back in the muscle car days of the late 60's gross horsepower ratings were used. This meant that the engine was tested without any auxiliary attachments such as fan, a/c or even a water pump. In 1970 the auto industry switched to net horsepower ratings which dyno'ed the engine with the auxiliary items attached. Additionally the ratings (then as well as now) advertised by the manufacturers were at the flywheel not the rear wheels (which usually results in about an 18% difference). So the 314 RWHP on that hemi was about 393 at the flywheel (using the net ratings).

Oh, and what's so great about the hemis? Well for one thing rarity (think Corvette L-88 and L-89) and the spark plugs are a hell of a lot easier to change than on an LTx. :D

I bet that the Hemi has a tad bit more torque than the LT4.

Mike

Those results have to be due to an error. I'm no Chrysler fan here but there was either something wrong with the engine, the dyno or the dyno calibration. Common sense would tell you it should run much better than that.

Greg

Technology marches on...look at it this way, it took roughly 30 YEARS to make a 350 production small block (LT4) to match the power put out by the 426 Hemi. That's pretty impressive for the Hemi in my opinion.

The Hemis were no slouch, those numbers are pathetic. There was something wrong there. That being said, in stock form in comparable cars, the 440 Six Pack would generally hand the Hemi it's lunch. The 440-6 was very under-rated at 390 HP. If you ever had the pleasure of driving one, you know what I'm talking about. :yesnod:

Let me see,Hemi anything verses a clapped out Corvette.The old Hemi cars are magic and C4 Corvettes are no where in this class,no where.You pretty much stepped in the middle of that one Chief.

It's mostly supply and demand. Very few original Hemi cars are still around. I would say that they were purchased with the intent to race it to the death. Most were. Besides that cars back them rusted out so badly most were scrapped long before they were actually worn out. The few that are still around bring big money.

That's the first thing I thought when I read the post.

:iagree: Both were awesome engines, headsnapping, hold-on to your a$$, get up and go. I had freinds with Hemi Road Runners/GTX's and 440-6 Challengers, man I can still smell the rubber burning.

:iagree: My cousin shoehorned a 440 Six Pack into a 1968 dodge dart, that originaly came with a 383. When he punched it, that car went every which way but straight. That was a fun car, & a real sleeper. :thumbs:

I owned a few hemi cars 70 cuda, 67 gtx (silver bullet) , and a 70 duster (a/gs). Much of it has to do w/stock trim, going into the latter 60's they made the street version. This consisted on inline 2x4, head change, and lowered compression (10:1). Earlier version had the crossram, 'k' heads and increassed c.r. with all that said they still posted the same numbers, for both versions. Numbers like anything really don't always tell the story.
Think of it this way, in 65-66 they offered a limited number a/fx cars it came w/injection, altered wheel base and weighed approx. 3100, with what would be considered mild cam an isky 590 (non roller) these cars went 9.19 on a 9" slick ! In 68-69 they offered the dart and barracuda lightened up version stock wheel base etc. motor came w/crossram, mild cam, k head, stock stroke. these weighed in at right around 3100, cars went 10's. from the factory! Now they played with numbers just like all mfg.s do but the hemi in particular was always considered de-tuned (after about 68) with any work (if the later prod. street version ) intake and headers would turn it into a beast even with the 10:1 piston. The original mopar race team used this slogan: "And on the 7th day god created the HEMI"
Someone posted above that it took 20 years for a small block to catch up this is true , however ther was a guy named "grumpy'' Bill Jenkins who was doing it in the 70"s.with great success I might add, it just took 20 years for GM to actually use some of the tech.

426 HEMI Engine Specifications . . .
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Street HEMI Engine Specs
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Engine Type: 90 deg OHV V8 (Hemispherical)
Engine Block: Cast Iron
Engine Heads: Cast Iron (Hemispherical)
Engine Mains: 4-Bolt (cross-bolted)
Crankshaft: Forged Steel
Conn Rods: Forged Steel
Pistons: Forged Aluminum (Hemispherical)
Bore x Stroke: 4.25" x 3.75"
Displacement: 426 cubic inches
Horsepower: 425 HP, 490 Ft-Lbs Torque
Comp Ratio: 10.25 to 1
CC Vol: 168cc min / 174cc max
Valve Dia: 2.25" Int, 1.94" Exh
Cam Type: Solid lifter (1966-1969)
Hydraulic lifter (1970-1971)
Cam Lift: .467" Int, .473" Exh (1966-1969)
.490" Int, .481" Exh (1970-1971)
Cam Duration: 276 deg (1966-1967)
284 deg (1968-1971)
Intake: Aluminum Dual-Plane, Dual-Carb
Carburation: 2 x 4-bbl Carter AFB
Ignition: Dual point, vacuum advance
Spark Plugs: N-10Y
Firing Order: 1-8-4-3-6-5-7-2
Exhaust: Cast Iron Headers, 2.5" outlet


http://img.photobucket.com/albums/v2...te/426cut1.jpg

Back when I was a kid my family (dad, uncles older cousins) were big block Mopar enthusiasts. I believe that the fastest Mopar (acceleration wise) that I rode in was a Duster that my grandfather shoehorned a 426 Max Wedge into. A few of my cousins had Street Hemi cars however, I never saw their taillights when I was in my 70 454 SS Motion Chevelle and I mean never, that Chevelle was scary to drive on a nice sunny day, and down right hairy in the snow or rain.


In my opinion hemis are rare because there were so many Mopar choices that provided performance that was close to even better the Hemi on the street and they cost a lot less money to buy and insure.
Mike

Did they have it setup to run leaded gasoline like it did in the 60's?

Did they run it with unleaded?

That would make a good bit of difference. :yesnod:

Myvettesblue spilled the key words: 490 lbs. torque :yesnod:

Look out-here it comes, the new Dodge Challenger 2006 is incorporating
a modern 6.1 liter Hemi engine-the new car looks alot like the original 1970 Challenger-wonder what that puppy is gonna do-not sure I'd want to line up against em :eek:

SAE net vs. SAE Gross is not relevant here. This was a dyno pull just like many of us have done with our cars. The quoted number is HP to the wheels so the factory ratings are not what I'm talking about.

What I really mean to imply is that the legend of the HEMI is much greater than the actual product. Strictly speaking of the street package sold on the showroom, comparable to big block Camaros or Chevelles. Yes factory Super Stock racers were full on mega horse machines, but that's not the car at issue here.

Our present day C4s match them very well. At Vintage Thunder two years ago there was a 440 6 pack Cuda or Challenger running with headers, slicks and open exhaust. He was turning mid 13s all day, while I was running 12.5 and 12.6 times. I drove in with full pipes, put on drag radials, and went out to stage.

The point is, even the LT4 cars that have been upstaged by the LS6 and LS2 newer Vettes are absolutely amazing in performance compared to original muscle cars.

And back then in 1969 my mild 396 325 horse Camaro never saw the taillights of a 440 Mopar.

Never drove or rode in a six pack, but constantly drove a very heavy, '66 New Yorker with the 440 de-tuned, 350 hp. It was funny to see a four door sedan hand some street "machines" its taillights. Torque-o monster.

Ahhh, Joel Rosen.....

:iagree: The wife's '71 R/T 440 Six Pack is much faster than any stock Hemi I know of. Even her brothers, who own a few Hemi's won't argue that point. The thing that made the Hemi's so popular was their potential to develope much more horsepower than what they put down in stock trim.
BTW, there is a green with white top Hemi R/T vert (66?) going over the block at the BJ auction next week that is one of two...bet it gets close to a million bid!