June 2015 hotrod

[63 dream'n]

The new Hot Rod Magazine on page 16, lists..... world exclusive we dyno test a 427 mystery motor built by Smokey Yunick. Tom McIntyre of Burbank California has one of the only running race versions of a mystery motor that's known to exist and he let hotrod dyno it up to 6300 rpm.the article states that the motor was spun the 6300 rpm where the power peaked at 446. 7 horsepower at 5700 rpm and 450.2 foot pounds of torque at 4700 rpm.At the end of the article, its a one page article, there is a caption at the bottom of the page it says........ hear it run.You can Google search mystery motor dyno test and you'll actually be able to hear it run.

 

[63 dream'n]

It's kind of funny that everything that I have read about the mystery motor previously, there have been many statements as to horsepower ratings...... and everything I had heard that the motor was in the 600 plus horsepower range..... strange!

 

[1961BelAir427]

Sounds to me like a Z11 would have stomped it.

 

[MRHP]

Well, how accurate were dynos back then compared to todays. That must be factored into the mix as well.

 

[jim_ss409]

Here's a link...
http://www.hotrod.com/news/world-ex...963-427-mystery-motor-built-by-smokey-yunick/

Video...
http://www.hotrod.com/videos/427-ch...y-smokey-yunick-gets-dyno-tested-23833/23833/

Did Chevrolet ever have a stated horsepower figure for the Mystery Motor?
I think I've heard figures like about 500 hp but that might just be what people thought or heard it made.
It seems like the manufacturers pretty much just pulled horsepower figures out of thin air back in those days anyway.
I think a lot of engines were a little over rated back then and I'm sure that would probably include our 348's and 409's
I'm guessing that a nicely blueprinted 425 hp 409 might have lived up to it's horsepower rating but I'm not 100% sure a random production line engine would have done it.

I remembered this post by Joe Sherman on Speedtalk. I looked it up and copied it here...

"When I was at Edelbrock back in the late 1960-1970== we got lots of brand new engines for manifold testing, and most of them were not even close to the advertiser HP and torque-A few examples--- A 271 Hp hipo 289 Ford made 197 on our dyno-- A 340 HP corvette made 312 on our dyno. Some of the better ones were the 275 HP rated 340 Mopar, really made 270 HP. amd the 335 HP rated 351 Cleveland made right at 320 HP- There were a few RINGERS--- A street Hemi, rated at 425, really made 465- Most were off by quite a bit, but some were not-- I am not surprised by this low HP number-Recently, I have run several 428 Fords ( stock type rebuilds ) and the are pretty weak--- Like around 330 Hp with dyno headers"

I notice that the Mystery Motor they ran in this test peaked at only 5,700 rpm so I'm guessing that another ten degrees of cam duration might have made it really come to life.

 

[jdk971]

i have never been a mechanic. i have been told that a dyno can vary in its readings. depending on the days temp, humidity and the operator can
can mess with the input info. i have always been told they are for tuning and testing. also those mustang dyno shops up their hp ratings to
make the customer feel better. personally i have no working knowledge. my ls3/480 in my vette with a 5 speed when it was tuning
produced a little above 350 at the wheels. jmho jim

 

[1961BelAir427]

That is pretty good Jim. That is right around a 25% loss compared to the advertised rating of 480. Chassis dynos like your car was ran on will always show a much lower number than an engine dyno measures "at the flywheel" because you have it in "full dress" with all the accessories and full exhaust and a lot of power gets absorbed by the transmission and rearend.

350+ rear wheel horsepower is respectful and should make it a fun ride.

 

[LMBRJQ 60]

I had a 350 in my 56 belair, TH350, 3.0:1 open wheeler rear end
Got dyno'd on a chassis dyno at 187HP

Ran 14.7 at 98MPH in a full street car with spare in the boot and tools etc as well

I was happy with that

Lynettes 60 is 305HP at wheels but it is 2.75:1 LSD 12 bolt
Gets off its butt at higher speed but pretty lazy around town

Steve

 

[Phil Reed]

Steve. .......how come Lynette's rearend is an LSD?????????

 

[LMBRJQ 60]

Steve. .......how come Lynette's rearend is an LSD?????????

You havent put a smiley on this so am i to assume this is a serious question?

Steve

 

[Phil Reed]

Is that enough? ?????!!!!!!!!

 

[LMBRJQ 60]

Is that enough? ?????!!!!!!!!

Steve. .......how come Lynette's rearend is an LSD?????????

LSD= Lovely Shapely Derriere (just in case there are women on here)

The 12 bolt is factory Pozi 2.75 or 2.70 or something like that, not sure what its out of but it fits and it the correct width
Horrible to try drive when it lets loose as you dont know what way the car is going to go

Need more practice

Lonnie can you pop over and teach me how to drive this 60??????

Steve

 

[Greg Reimer]

Was this engine's owner, Thomas Mc Intire(possibly spelled with an E), the head automotive instructor at Pasasdena City College in the early 1970's? If so, I was one of his students. He had all kinds of interesting stuff even back then. Hot Rod did a story years ago about the Ball Stud Hemi, a prototype engine Chrysler developed to replace the 400 and 440 inch wedge design, notable in that it had stamped steel stud mounted rocker arms, and Dick Landy had a few of them, hence the article in Hot Rod. Back in the day, the back rooms held treasures the likes of which we will never know.

 

[63 dream'n]

Was this engine's owner, Thomas Mc Intire(possibly spelled with an E), the head automotive instructor at Pasasdena City College in the early 1970's? If so, I was one of his students. He had all kinds of interesting stuff even back then. Hot Rod did a story years ago about the Ball Stud Hemi, a prototype engine Chrysler developed to replace the 400 and 440 inch wedge design, notable in that it had stamped steel stud mounted rocker arms, and Dick Landy had a few of them, hence the article in Hot Rod. Back in the day, the back rooms held treasures the likes of which we will never know.

Greg,look up the video clip Jim listed above.The gentleman who owns the engine is briefly interviewed

 

[Last 60]

LSD= Lovely Shapely Derriere (just in case there are women on here)

The 12 bolt is factory Pozi 2.75 or 2.70 or something like that, not sure what its out of but it fits and it the correct width
Horrible to try drive when it lets loose as you dont know what way the car is going to go

Need more practice

Lonnie can you pop over and teach me how to drive this 60??????

Steve

Would LOVE to, but I'll be doing good to get to Bowling Green!! THANKS for the invite, I'll keep that filed away in whats left of my feeble mind!

Lonne

 

[Greg Reimer]

No, that's not my old automotive instructor, although they are probably about the same age.That was neat seeing that engine run. That thing is way more rare than a Z-11. It would be fantastic to set that engine back into the correct car. I seem to remember a set of multi piece cast exhaust manifolds for it that were quite exotic- saw them in an old car magazine from that day.Now, I got a slide rule scale years ago that was a horsepower calculator. You went to the track,made a pass, and it told you how many pounds per horsepower your car made,based on the car's MPH. You weighed your car on the track's scale, divided the large number by the small number, the result was horsepower at the flywheel. My rather stock 409 2X4 engine I had in the early 1980's made an actual 420 horsepower. A dyno tune check like this of an actual fresh but correct Z-11 would be an interesting set of numbers, especially with one of the ultra rare NASCAR single four barrel carb intakes and equivalent carb to the Mystery Motor. Anybody want to do this?

 

[dakota tom]

This engine may have been detuned a bit for the Corvette. 1963 tires were not great and a wide powerband would be better than a max hp build.

 

[chevytaylor]

The new Hot Rod Magazine on page 16, lists..... world exclusive we dyno test a 427 mystery motor built by Smokey Yunick. Tom McIntyre of Burbank California has one of the only running race versions of a mystery motor that's known to exist and he let hotrod dyno it up to 6300 rpm.the article states that the motor was spun the 6300 rpm where the power peaked at 446. 7 horsepower at 5700 rpm and 450.2 foot pounds of torque at 4700 rpm.At the end of the article, its a one page article, there is a caption at the bottom of the page it says........ hear it run.You can Google search mystery motor dyno test and you'll actually be able to hear it run.

Dyno numbers are just that.......................numbers. If that is a real race Smokey 427 mystery (Rat) engine then place it in a well prepped light weight 63 sedan with drag gearing etc, put Jason Line behind the wheel and the true HP and torque numbers would be unveiled with it's 1/4 mile performance. Place an engine on ten different dynos and you will get ten different numbers. Dynos are great for breaking an engine in, or air fuel readings etc but most of the time the numbers they spit out are BS!!!

 

[MRHP]

I am not sure what you meant Carl, could you be a little more clear?

 

[chevytaylor]

some people mentioned boredom on here, just stirring the pot MRHP