how many people tell the truth about horsepower? do you?

[cudaken]

In the latest issue of Mopar Collector's Guide, Ray Barton rebuilt a 71 426 Hemi from a GTX to stock spec's (I'm sure he did some blue printing, and dyno tuning) and it made 498 horsepower at the crank.

Moparhound, I don't think Ray Barton remembers what a stock Hemi is . With his rep as a racing engine bulider he had to make thoses kind of numbers. Sure he used is 25 years plus of tricks that would pass as stock to the naked eye. More than likely played in side on the intake, messed with the runners. Match poreted everthing, maybe just a little pocket work, blue printed deck height, custom cut push rods, had the stock manafolds hogged out a little.

Don't get me wrong, I never said a Hemi could not make well over 425 HP. But not the way they where made at the factory. Same with the other egines I listed, but we are talking about the way they from the factory.


                        Cuda Ken

                       

[Jon Smith]

An engine built by a top race engine builder is not the same as one built on a production line by someone who's not interested and is probably thinking about the few beers he's gonna have later on

[Blown70]

I think for ray barton to build to hemi specks he would have to use the equipemnt from the era.... I am sure the tolerances on his equipment is NOT the same as 30+ years ago.  Parts esp metal are made better today than yester year....

Also, define stock specks,  as pointed out above Friday at 4:30 as a shift would end well do you really think the same attention was paid?

[firefighter3931]

Right cudaken....You beat me to it

In the back of the old direct><connection engine book is the drag strip dyno   The formulas work great as long as you know the weight of your car with you in it and the trap speed at the dragstrip


Here are copies of the charts below. Try it on your car

Interesting charts Cuda, thanks for posting them. Using the formula provided and comparing power to weight ratios with MPH using my own car i come up with 119 mph which is good for low 11's.

4000lbs/535hp = 7.47lbs per hp (auto trans)

As per the chart, that falls between 118 and 120 mph in the 1/4 mile. I haven't run it yet but will next season....should be interesting to see how close the chart is to reality. I know it has plenty for mid 11's but low 11's would be a pleasant surprise.

Ron

[MOPARHOUND!]

In the latest issue of Mopar Collector's Guide, Ray Barton rebuilt a 71 426 Hemi from a GTX to stock spec's (I'm sure he did some blue printing, and dyno tuning) and it made 498 horsepower at the crank.

Many a story out their about 426 Hemi's off the show room floor running poorly.   Talked to Mr. Norm of Grand Spaulding Dodge at this year's June www.hpacmopar.com club Mopar show in Kansas City, and he said getting the timing right and tuning the carbs made a world of difference on the car's new.   He said his dyno was one of the greatest investments he ever made.

Just the messenger.  Thought it an interesting angle to add to the debate/discussion.   

[MOPARHOUND!]

An engine built by a top race engine builder is not the same as one built on a production line by someone who's not interested and is probably thinking about the few beers he's gonna have later on

Hence, they run poorly when new.

I've heard one story of a guy so frustrated getting his hemi to run, he pulled his hemi back in the day for a 440.

Same Mopar Collector's Guide, page 128 concerning a 70 Hemi Challenger, "Then, to Jose' and Gus' absolute horror, they discovered what a number of new Hemi owners found out quickly - the car was a dog!   As delivered, the Challenger with the big Hemi was getting spanked by small block Chebbies. ........ The Challenger went through the full dyno treatment at Mr. Norm's within a few months of being new, after which it performed like the lion it was supposed to be."

Cool thing is they show the March 31, 1970 dyno receipt from Grand Spaulding Dodge, $13.65 for parts and $56.95 for labor.  Roughly $80.00 for a dyno session, that would be sweet.

Wish they would have listed the dyno numbers.     

[Baracda]

Its not working right now for some reason but there is a really nice website at www.prestage.com that has a number of active plug n play formulas for everything from dyno-generated shift points to piston speed to HP/MPH calculations.   The site has been around for 8 years or so, be patient with it and it will be up again soon I hope.

Whats interesting about this HP discussion is how it relates at the track.   Its funny how many bench racers use the ET as the generator of HP and its nice to see the old DC charts developing the actual HP relationship based on Work/Time.   Thanks for posting them.   Moroso used to make a really neat paper slide rule calculator that did the same thing but I dont have one anymore.   

The suspension plays into this so much that you can get strange anomolies of an ET with a car thats not set up "right" for the track.   My car has a tight suspension both front and rear and runs a nice MPH but the ET is way way off.   A typical slip reads as folows:

60ft - 1.643
1/8 ET - 6.789
1/8th MPH - 107.37
1/4 ET - 10.606
1/4 MPH - 131.67

My ET is way off what the MPH would indicate.   This is with a 3200 stall convertor which doesnt allow enough stall to let the motor move up into the power band when I hit it.   The front only comes up about 5 or 6 inches but the front suspension doesnt drop, it carries it with the front end.   The car weighs 3720 lbs with a 540" with 9.3:1 compression.   And the irony?   The only time I took the car to a dyno it made a max hp of 480 and a max torque of 510.   Thats why I dont trust a dyno.   The track NEVER lies.

jim

[Jon Smith]

theres a spreadsheet here with all kinds of calculations just click on where it says auto math on the left hand column
http://www.dodgechallenger.co.uk/

[Ghoste]

Keeping the hp numbers out of it just for a moment, something to consider when hearing stories of how poorly Hemi's ran when new is this.  Virtually every performance engine of the supercar era began life as a regular duty engine and it was hopped up to make it run hotter.  The Hemi was a race engine that was detuned to make it streetable.  When the ordinary performance mill falls out of tune, it still can perform adequately on the street.  When a Hemi falls out of tune, it's screwed.  And yes, they can be brand new and still be out of optimum tune.

[MOPARHOUND!]

Its not working right now for some reason but there is a really nice website at www.prestage.com that has a number of active plug n play formulas for everything from dyno-generated shift points to piston speed to HP/MPH calculations.   The site has been around for 8 years or so, be patient with it and it will be up again soon I hope.

Whats interesting about this HP discussion is how it relates at the track.   Its funny how many bench racers use the ET as the generator of HP and its nice to see the old DC charts developing the actual HP relationship based on Work/Time.   Thanks for posting them.   Moroso used to make a really neat paper slide rule calculator that did the same thing but I dont have one anymore.   

The suspension plays into this so much that you can get strange anomolies of an ET with a car thats not set up "right" for the track.   My car has a tight suspension both front and rear and runs a nice MPH but the ET is way way off.   A typical slip reads as folows:

60ft - 1.643
1/8 ET - 6.789
1/8th MPH - 107.37
1/4 ET - 10.606
1/4 MPH - 131.67

My ET is way off what the MPH would indicate.   This is with a 3200 stall convertor which doesnt allow enough stall to let the motor move up into the power band when I hit it.   The front only comes up about 5 or 6 inches but the front suspension doesnt drop, it carries it with the front end.   The car weighs 3720 lbs with a 540" with 9.3:1 compression.   And the irony?   The only time I took the car to a dyno it made a max hp of 480 and a max torque of 510.   Thats why I dont trust a dyno.   The track NEVER lies.

jim

Welcome to the site Jim.  540" with 9.3 compression, runs on pump gas I bet.  You have a PM.

['CUDA360]

360Cuda, I want my bible back
What year is your DC Manual 360Cuda, my last one is 1978.

                         Cuda Ken

I'm not sure what edition this book is because I read it so much it fell apart so I put it in a book binder. I can tell you the date on it is 1989 so it's at the end of the direct><connection program when it became Mopar performance.

Hey Firefighter
You might be right on your performance estimates but it should take a while before you get to the 11s.
The 60ft time is a great tool for this. Pick the right converter/gears, slick size and suspension mods.
My friends and I spent time playing with the clamps on the front of the rear springs as well as shocks and some ballast. The low gearset in the 904 transmission helps too.
I got my 60 ft down to 1:59/1:60   against Camaros and Chevelles with 1:80 and above 60 foots.
Those cars had faster times at the end but I left on them so hard I might have rattled them a bit as I pulled the front wheels a little off the ground   

I could just picture them sitting there waiting for their light to come down as they watch my 12 second small block car run away like a bat out of hell.

[firefighter3931]

Hey Firefighter
You might be right on your performance estimates but it should take a while before you get to the 11s.
The 60ft time is a great tool for this. Pick the right converter/gears, slick size and suspension mods.
My friends and I spent time playing with the clamps on the front of the rear springs as well as shocks and some ballast. hell.

Thanks, i've settled on a suspension package as well as converter and gears. Based on the dyno data, i decided on a 4500 stall and 4.10's. The engine made peak torque at 4400. Peak hp came in at 6000. Doing the math : 6000 rpm with 4.10 gears and a 28in tall tire is 120 mph....pretty much where i want to be. The suspension is a set of 3800lb b-body SS springs and Comp Engineering adjustable drag shocks front/back....i've seen this combo work well for many years. I expect it will 60 ft somewhere in the 1.50 range with the 28 x 10.5 Hoosier's. I'm not sure if the car will reach 120mph before it eats up 1320 ft but i bet it'll be close. I had done the math previously and your chart backed up my own calculations....i hope we're both right....

Ron

['CUDA360]

Cool 

[cudaken]

 Mine is still in pretty good shape, the first one along with a dealship manuel feel apart from reading and re reading.

Does anyone know if the current MP program have a manuel like it? If they do it is a must read, or see if you can find a old one. It would really cut down on some of the silly post like from me

One of the cool things in the Mopar Bracket Racer Science (360 Cuda that is what my chapter is called) helps you know where you want to start, slecting body, engine, yearly mileage, # of trips to the track a year, Acceptable Free Way speeds, Fuel Economy (seems funny now when talking old Mopar) number of cars you have (means when you break the one you are working on ) and the list goes on. Kind of lets you know up front what you are getting your self into.

Best 869 pages of writing I have ever read.

                                   Cuda Ken

[Ghoste]

Very much so Ken.  Only now they split it up over several manuals.  There is a chassis one, a Hemi one, a big block one, and so on.

[cudaken]

 Ghoste would you happen to have a part number for Big Blocks, transmission and rear suspention?
Like to get a little more up to date information.

                                   Cuda Ken

               

[Ghoste]

The current big block manual is P4876 825 and the chassis manual (which covers trans and suspension) is P5007 160.

[cudaken]

 Ghoste, thanks

                             Cuda Ken