HP Question/ Estimate

[Baumi]

My rebuilt 327 sbc ´s just had its 20 minutes of breaking in and it sounds pretty healthy . I wondered what amount of HP and Torque one might get out of an engine like that.I´ve used pretty common parts, so I hope an estimate is possible.
The block is a 3970010 2 bolt with 4.040" bore
Pistons are speed pro L2166nf.040 with .125" dome
heads are 3991492 with 2.02/1.60 valves and 64cc chamber,
CR should be about 10.5 :1
the ports have been cleaned up slightly
cam is an Edelbrock performer rpm and so is the intake manifold
the carb is an 600cfm Edelbrock
Unilite distributor
and last but not least tube headers and 2 1/2 " exhaust tubing.
What rpm would you recommend as a maximum?
Would I be too optimistic if I said about 240 to 250 Hp?
Thanks for your input!

Baumi
http://www.image-hosting.net/images/messageboard/SmokinMike/sbc2.JPG

[C9]

The factory got 283 HP out of the injected 283 engine.

I'd venture to say you're flowing air slightly better considering the Edelbrock intake manifold and cam.

HP figures probably range from 285 - 300.

If you can run the car at a dragstrip and get a MPH figure and supply the weight of the car as well as the differential ratio I have a couple of things that will compute HP.
ET is interesting, but not necessary.

You probably know this, but here it is anyway -
MPH reflects HP
ET reflects chassis tune.

[Deuce Roadster]

[ QUOTE ]
My rebuilt 327 sbc ´s just had its 20 minutes of breaking in and it sounds pretty healthy .


Would I be too optimistic if I said about 240 to 250 Hp?
Thanks for your input!

Baumi





[/ QUOTE ]


The mid 60's 327 350 HP Chevrolets used very much the same pieces you have with a little more compression (11 to 1) so with a .040 overbore, port matching and your upgrades......I feel 300 to 325 is real easy to get. Just my 2 cents....

http://www.jalopyjournal.com/ubbthreads/images/graemlins/crazy.gif

[wingnutz]

[ QUOTE ]
The factory got 283 HP out of the injected 283 engine.

I'd venture to say you're flowing air slightly better considering the Edelbrock intake manifold and cam.

HP figures probably range from 285 - 300.

If you can run the car at a dragstrip and get a MPH figure and supply the weight of the car as well as the differential ratio I have a couple of things that will compute HP.
ET is interesting, but not necessary.

You probably know this, but here it is anyway -
MPH reflects HP
ET reflects chassis tune.

[/ QUOTE ]

C9 can you post the formula for the MPH to HP ratio???

Plus isn't that formula set up for Rear wheel Horsepower?

Mark

[Baumi]

Thanks guys! Around 300 HP seem to be realistic then I guess. That´s by far more than I´d expected.

Mark, I´ve just googled for " horsepower calculator" and I´ve found dozens of pages. Here´s one formula I ´ve found:
----------------------------------------------------
Simple Horsepower Calculator
NOTE! This is just an estimate, and is probably not all that accurate.
This program will give you a ballpark estimate of your horsepower. Please don't make the mistake of quoting these numbers as if they meant anything.

There are two simple horsepower formulas that can estimate the on-the-pavement horsepower for a given car.

The ET method
This method uses the weight of the car and the time it took that car to travel 1330 feet (¼ mile).

The formula is: hp = weight / (ET / 5.825)3




The Trap-speed method
This method uses the weight of the car and the speed at which the car completed the quarter-mile run.

The formula is: hp = weight * (speed / 234)3

Let's try it
Fill in the data below.


--------------------------------------------------------------------------------

How much does your car weigh (with you in it, of course)? lbs
What was your 1/4-mile Elapsed Time (ET)? seconds
What was your 1/4-mile Trap Speed? mph

___________________
I ´ve no clue if those formulas are correct, but I think someone around here can tell you.
Baumi

[tomslik]

where does areodynamics fit in?
easier to make a 4000 pencil go a 100mph than a 4000 barn.

[Baumi]

[ QUOTE ]
where does areodynamics fit in?
easier to make a 4000 pencil go a 100mph than a 4000 barn.

[/ QUOTE ]
That´s a good point....

[wingnutz]

OK ..., I've run the numbers and I seem to be a decimal space off!

My 2000# Roadster Ran 10:92 @ 123 MPH..., according to my calcs on the ET formula my number was 3200.5494..., should the decimal be after the 320? If so another step of division by ten should be added and I'd say that 320 HP at the rear wheels sounds about right!

Trap Speed Formula divided by ten came to 315.3846 HP Rear Wheel..., again seems right!

My dyno hp at the crank was 503.922 and about 478 Ft Lbs of torq and I was told that the tranny and QC would rob me of about 175 HP!

I think my trap speed HP would have around 320 HP if I wasn't "Pushing" so much wind with the stock height windshield!!! http://www.jalopyjournal.com/ubbthreads/images/graemlins/tongue.gif

I never knew that Glass could bend so far without breaking!!! http://www.jalopyjournal.com/ubbthreads/images/graemlins/crazy.gif

Thanks

Mark

[AHotRod]

I'd say 340-360 HP Max.

[Machinos]

Wow, 175hp lost in the drivetrain? That's nuts...

[wingnutz]

Yeah..., that's what I thought!

Automatics and Quickchanges weigh more and create greater friction that tend to eat up Horsepower!

You loose less HP with a manual tranny and a 9 inch rear!

Wheel and tire selection will play a big role in the loss factor as well.

Mark

[Flat Ernie]

[ QUOTE ]
Wow, 175hp lost in the drivetrain? That's nuts...

[/ QUOTE ]

I've always heard you lose some percentage of power everytime you change directions with a gear. So with a 4-spd manual, the most you're ever changing directions is three times - twice int he tranny & once in the rear-end. Whereas with an automatic - I couldn't even begin to count how many times you're changing rotational direction with all the sun & planet gear sets. Not to mention the inefficient converter. Throw a quick-change on & you just added two more...

While it sounds like a lot, it doesn't seem out of the realm of possiblity...

The number I heard way back when was 10% loss for every change of direction with a gear...

Anyone else ever heard of this nonesense?

http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

[Baumi]

[ QUOTE ]

HP figures probably range from 285 - 300.

If you can run the car at a dragstrip and get a MPH figure and supply the weight of the car as well as the differential ratio I have a couple of things that will compute HP.
ET is interesting, but not necessary.

You probably know this, but here it is anyway -
MPH reflects HP
ET reflects chassis tune.

[/ QUOTE ]


Thanks C9

There´s no dragstrip around here ,so I won´t have a chance to race the car in the near future.

( what doesn´t mean that I won´t race at all, just not on the dragstrip http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif).

It´s a 56 chevy, so it´ll need more than an sbc to make it a race car, a Caddy 500 would probably do the job better. But that´s not the way I´m going.

I ´d like it to perform good and to be reliable on the highway. The tranny is a TH 350 with stock converter and the rearend has 3.36 gears.I still have a pumpkin with 3.55 gears.

Will my setup, as it is now( 56 Chevy 2dr/327/Th350/3.36 gears) have a torque problem with the stock converter?



Baumi

[JOECOOL]

Don't write off the automatics so fast , converters have a nice feature ,it's called torque multiplication. A good converter will put out more torque than the engine is putting out. Automatics also vary with the amount of HP used . A turbo 400 eats power but has a low gear ,350's are better but not as low geared.
If you have the right converter a power glide is the best. Low drag ,low weight ,pretty darn strong and they used to be cheap.
Just my opinion I could be wrong.

[wingnutz]

We ran a Glide for 8 years with a BBC in a 67 Chevy II..., Great set-up and run consistent 8.7 @ 167 with 1.24 sec 60 footers reading off the rear wheels!

Past year we switched to a "Bruno-Lenco and gained one tenth of a second and 4 MPH with everything else remaining the same!

I like Automatics and got great torq Multiplication from the torq coverter as well as the Drag slicks!

But the Lenco with a new torq converter seems a little more efficient and "Fun" to drive...! http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif

Mark

[wingnutz]

Baumi, is that going in your 56 or 62 Chev?

I had a setup like that in my 56 Chev and it was Impressive!

Mark

[repoguy]

Considering the fact that the weakest 327 ever made was a 2 barrel motor with 8.75 to 1 pistons, and it made 200 horses, I think 240 to 250 is a very conservative estimate.