So I just watched an episode of American Muscle Car that I had recorded where they took 5 stock motors and put them on an engine dyno to see who made the most power. They were supposedly all stock restorations with no more than a .060 overbore, stock style and sized carbs, open headers, no accessories.

The motors were as follows:

Chevy 409: 406hp
Pontiac SD 421: 488hp
Ford 427: 637hp
DC Hemi 426: 820hp
Chevy L88 427: 527hp

Now I'm a bit of a skeptic. My first problem is that the first two motors were run on one dyno while the last three were run on a different dyno. Now if the L88 had been run on that dyno also I would chalk the big Ford and Hemi numbers up to the different dyno but 527hp seems reasonable from what I've heard about the L88.

So my question is this, if the bone stock 426 Hemi can really make 820hp, and it's some port work and a cam away from the magical "2 per cube" horsepower mark, why am I wasting my time with these Chevy motors? Or is there some gross error that I'm missing?

 

Ya think that Hemi was a little "preped"?

 

Somethings not right. If they were all relatively stock then the hemi would have made closer to 500 hp. It was factory rated at 425 hp and the engineers knew that was low but they had to do it for insurance reasons.

The 409 is a poor example for performance. It was good in it's day but by today's standards, it's poorly designed.

If you want real world comparisons look at NHRA Stock Eliminator racing. The 69 Camaro with the aluminum L88 is matched up to Hemi powered Cuda's. Under the A/SA class rules, the cars are very similar to power and weight. Although the Camaro was the first to get into the 9's, both are capable of doing it although they normally run very low 10's.

Now when you get into SuperStock were more modifications are allowed, the Hemi dominates most of the time in the normally aspirated cars.

Mustang dynos are also notoriously bad at giving overinflated results.

 

Either that or the room was kept at a nice 2x atmospheric pressure.

That still seems like a whole lot of power out of 60's technology though, I mean that's still pretty close to 2 per cube with stock appearing heads and intake, and "claimed" stock displacement.

I think they are going to continue that episode with more engines, I can't wait to see what the LS6 puts down.

 

Wasting time on a chevy?

Well everyone thinks LS heads really work good.....Look into flow numbers from stack 351C castings from ford. I have seen stock castings worked by Eric Bradby that flow in the hi 350's and have wild low lift numbers.

All makes have good stuff that will run its *** of in the hands of the right person. But stock for stock I think all those numbers are wayyyyy off

 

there is no way in hell that is accurate. i know that the hemis burn more efficiently but not that more efficiently. either they were using jet fuel or something. i have seen mammoth numbers come from a L88. something doesnt add up.

 

As I said, I'm a skeptic.

If a bone stock 426 hemi can put out 820hp with a 60's era carb and flat tappet camshaft then I need to build one. However, this thread is more to find out how they came up with these numbers.

 

The low lift on the 4V heads is due to that big *** valve in there... not saying that's good or bad just depends on where you come from.

Looking at a 4V Cleveland head with a 2.20" valve and comparing that to a 2.100" LS6 head moving the same air, I'll take the LS6.

 

I would too bret...but look how old the cleveland stuff is and still makes o.k. power now days. That design is what close to 30+ years old......you can do alot of R&D in that time.

Indy cyl heads has got those newr heads out with the raised ports, they are some bad mfers

 

Well the Cleveland spawned the Yates (and a few other custom Ford castings at the time, they settled on the Yates) then that led to the SB2, then SB2.2, P7, then Toyota and now the RO7 head. It really is the only good design from the 60's but in comparison to a LS7, it's really a pile IMHO

 

everything i have found on the hemi cars says around 465 tops....look at what went on in nascar and NHRA.......that will tell you what was happening. Your show must have been sponcered by mopar

 

It wouldn't surprise me at all

 

That Hemi was no where NEAR stock, that show was a re-run. The first time it was shown there was a HUGE stink about the Hemi not being stock on alot of boards.

To make 800 hp on pumpfuel It was almost certainly a stroker engine.

Think about it, if it WERE a "stock blueprinted" build, there would have been 9 second street Hemi's everywhere in the 70's...NOT!

I really cant believe that had the stones to air that show...TWICE!

David

 

I bet I am the only person here who owned a Hemi car "back in the day" and it DID NOT have 820hp. Period.

Rich

 

My dad owned a factory altered race car that in the 60's was pretty radical.

I don't know what the car weighed, but I would guess around 3000 lbs. race weight.

The best timeslip I have is a 10.09@137.61 mph. This was in an unaerodynamic car.

While this was obviously not the day to day Hemi, it came that way from the factory.

So maybe they got their hands on one of those motors?

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