MoPar rated the hemi as 425 HP @ 5000 rpm. What they neglected to say was that the dyno pulls went to 6000 rpm, and at 6000 revs, the engine put out 495 hp. There is a content provider on KZfaq, "Nick's Garage" and he has a weekly show specializing in MoPars. Particularly he works on a ;lot of 440s and hemis, although other engines come into the shop as well. In one of his shows he re-created a stock spec 426 hemi, totally stock except for a .030 overbore. He then ran it on his SuperFlow 902 dyno, and that's what it put out. Sure enough, at 5000 rpm it was 425 hp, but at 6000 the totally stock hemi put out 495 hp.

I have a 1969 Car Craft magazine issue in which they drag race test a 69 Roadrunner 440 6 pack automatic. They fiddled around with it and got some decent times out of it with slicks. As evening approached they realized the exhaust manifolds were glowing red hot after each pass and obviously a set of headers were needed. I've seen a true survivor Hemi Roadrunner that was absolutely bone stock but most people that bought a Hemi car for performance NEVER left it stock. A set of correctly made headers that match the stock cam and a correctly recurved factor distributor and the factory carbs rejeted by someone who knows what they are doing is worth 65 horsepower minimum so who gives a flip what the engine would do off the showroom floor ??

Engine Masters tested the 426 Hemi vs a 440 and it turned out the hemi was great for….high sustained rpm but the 440 made killer torque for drag racing

Thanks for your approach to this Hemi build. The HP of these engines are all over the place. This is a good approach at what might have been delivered to the public in the 70’s. The Hemi is the most legendary engine offered in the 60’s and 70’ s and that is without a doubt. You either wanted a Hemi or you wanted to beat a Hemi. It was the litmus test on the street. Wether it lived up to the hype or not is not the answer. As legends go it got bigger and bigger in street lore. And as the top engine used in top fuel it also backed up the hype. Yes an LS6 454 is legendary too. As is the 427 Ford. Even small blocks have status. But the Hemi sits on top because of the hype. I have never owned a 2nd Gen. Hemi but I drove one one time in 79. A 66 Hemi Charger automatic. And I only got into it a little bit. But the torque was without question evident to me. If you wanted a Hemi to rule your streets, it took more money and wrenching. But it was an awesome starting package. Headers and a high lift cam would give back startlingly results. But tuning the distributor and carbs was a must after such modifications. The Hemi was a detuned race engine. And you had to return it back to what it needed to be with the right parts. You could go full bore and add 12:1 pistons and oil mods too. It was just what you could afford to do. Same with the other big blocks available at the time. It was definitely a different world in those days. And I miss them. Simpler times. Thanks for the video.

How is a 9.6 compression the right number you were looking for? The street Hemi had 10.25 compression. As far as horsepower numbers go none of the big three were telling what the true horsepower numbers were as they always picked a lower than peak RPM numbers to give the insurance companies what they wanted power wise.

The factory ratings were gross hp, no water pump, no air cleaner, fan, alternator, ps pump or full exhaust system. You’re running a water pump but also a .060 overbore so probably balances out. Cars today are rated on a net basis with all accessories in place and the full exhaust system. Be interesting to see a true net run on one of these to see how they compare to modern engines.

Beautiful Cuda. I'd rather have a tribute car than a museum piece you're terrified to drive and have fun with. Drive it like you stole it!

People dont realize the StreetHemis were detuned race motors, which dont work real well on the street in daily use. A well tuned stock 440/6 will out run a Hemi half the time. We ran a 64 RaceHemi with aluminum heads and a Hilborn injector system in a steel 37 Willys coupe and it put out way more than 650hp on a basically stock motor (no wild cam or exotic stuff other than the injector and magneto)

Nick's garage built one to stock specs too. It made 490tq/490hp.

Your 0.060" Over puts you near 440 cubes...My personal New car (With 4.10 Dana gear) experience, 1970 Factory hemi usually arrived 173 cc's heads & the way Down in the hole deck Height put the typical Actual measured CR at 'bout 9.0 :1 CR....The Factory as Delivered 1970 juice lifter Hydraulic cam literally Stops making Rpm (Like an rpm Limiter) at 5200 Rpm in high gear....Pre--1970 factory Solid cam engines (Like your Test engine example) have the usual >5200 Rpm gradual Tapered power roll--off curve....The Average as Delivered factory 1970 hemi (13.5 Et/105 mph) strong but Not quite good as your Solid lifter version...Too bad Chrysler took their fine Highly developed 570 hp Factory race hemi & Castrated De-tuned it (Very low CR + Small low Lift, short Duration cam) Down to the Crippled (Potentially capable) Lame fixed Single option Production version....Is as it Is (was) for a factory Homologation only engine...Imagine a Serious effort '69 A10 Equivalent (Liftoff 'glass pinned Hood, >11:1 CR, big Solid (>300°) Cam, Cross-Ram dual Holley intake, 3500 Stall) Available option Package.....Serious Factory "Domination" performance level street Threat !!....

Correct me if I’m wrong, but it’s my understanding that the 70-71 Hemis were hydraulic cammed. I love to see the difference of the 70s Hemi vs early models with solid lifters.

Hey thanks for the response on compression. I love watching the videos, have a great day. Thats crazy how the actual numbers would that off.

Smooth job, guys! Mopar queen and the king of engines💪 Perfect!👌

Great video there Kevin love to see them all cars back on the road in excellent shape great horsepower and torque love the video

Awesome video. 👍 My Mopar is my 1968 Barracuda fastback powered by a 400 based 512 stroker featuring Trick Flow 240 heads and a hydraulic roller cam with 254 duration @.050 with 618 lift, backed by an A833 4 speed manual. 👍

Thanks for that awesome demonstration of the beloved hemi!🇺🇸

Thanks for sharing great video

Nice to see some honest work giving honest numbers.

My wife has a real 71 Cuda, 340 4 speed, Bahama yellow. Needs a full resto, which is on my list, but for now it's protected

Thx for truthful informative video...Your Dyno performance numbers seem just about right..With 1000 miles, my factory pure stock '70 hemi cuda Automatic click off 13.1's @ 107 all summer day long with full gas tank @ 4000 lbs.....Carbs never Touched, 4.10 Dana, 35° timing ....