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Discussion Starter · #1 ·
This is what I got... Who can tell me what HP it will make?


4.052 Bore
3.875 Stroke
252 Duration @ 50?? -- 206 ea(whatever the hell that means) 420 lift 112* separation (I hope someone can make sence out of that mess...)
Intake Valves 1.9425 OD. 1.6875 ID .2480 Depth
Exhaust Valves 1.6300 OD. 1.3120 ID. .2175 Depth
Intake valves have a 3 angle grind.

No head work.

Stock 650/700 cfm. 4bbl rochester 4jet carb.
Standard compression is 10.5 in this car.
I used stock felpro head gaskets that are within a couple mills of the factory gaskets.

What does anyone think?

Gary
 

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Need a little more info? What motor is it? What else is done to it? Post your cam card? What kind of intake? is it a 650 or 750? What heads? Headers or manifolds?
 

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Discussion Starter · #3 ·
It's probably a 650 cfm, and the motor is a 1960, 390 CI Cadillac, the current cubes are 400 the original HP is 325 @ 4800 430 @ 3100 BHP. There is no cam card... what I typed is what you get unless this will work...>>
252 advertised duration
206 @ .050
.420 lift
112 LSA

Stoch heads stock exhaust, stock intake. Which motor is kind of moot if the HP calculator takes bore and stroke into the calculations.... That's why I didn't state the motor size, it is the bore and stroke, right?

FE


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<font size=-1>[ This Message was edited by: FEandGoingBroke on 3/16/06 3:08am ]</font>
 

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around 275-300hp depending on engine condition, Close to factory, They where rated differently years ago.
 

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i think 260ish if it has stock intake manifold and exhaust manifolds. What kind of engine isnt completely moot though because of stock cylinder head and intake manifold design
 

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Discussion Starter · #6 ·
Hmmm... If the HP copnvertor Programs take into account the stock proportions then they might NOT be able to come up with any HP ratings for this motor... It was only a 4 year application and ONLY in cadillacs, not in any other GM product...

How did they compute the HP of old? Anyone care to fill me in?

FE
 

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Most of the lower end computer programs over rate the engines you put in them. Alot ot those really old heads are very bad flowing examples. One of the Engine Guy's on her could chime in and explaine SAE Vs other ratings.
 

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Different correction factors. Without Accessories, No air cleaner, Etc.
 

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When the factory rates engines now the rate them with accessories, aircleaners, exhaust Etc. They used to cheat and dyno the engines without the things that take HP to run.
 

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Discussion Starter · #12 ·
Below is what I got from a google search. Does anyone have a calculator that estimates HP like they did before 1970? Or is there and estimated ratio that play's into the end results of "today's" HP calculators that will approximate the older BHP style? I would like to know how much diffrence I have made in this motor power wise, but I want computed estimates rather than gusses like ""This cam"" does ""This much..."" Etc...
The original HP rating was 325 @ 4800hp and 430 @ 3100tq. I understand that this was estimated at the flywheel with NO accessories and whatnot, and since it was what would these #'s translate into under SAE requirements?

These are big questions but I'm curious...




Brake horsepower (bhp)
Brake Horsepower (bhp) - The measure of horsepower at maximum engine output, minus power lost from heat, friction, expansion of the engine, etc.


hp (SAE)
In the United States the term "bhp" fell into disuse after the American Society of Automotive Engineers (SAE) recommended manufacturers use "hp (SAE)" to indicate the power of the engine, given that particular car's complete engine installation. It measures engine power at the flywheel, not counting drivetrain losses.

Prior to 1972 most American automakers rated their engines in terms of SAE gross horsepower (defined under SAE standards J245 and J1995). Gross hp was measured using a blueprinted test engine running on a stand without accessories, mufflers, or emissions control devices. It therefore reflected a maximum, theoretical value, not the power of an installed engine in a street car. Gross horsepower figures were also subject to considerable adjustment by carmakers: the power ratings of mass-market engines were often exaggerated, while those for the highest-performance muscle car engines were frequently underrated.

Starting in 1971 automakers began to quote power in terms of SAE net horsepower (as defined by standard J1349). This reflected the rated power of the engine in as-installed trim, with all accessories and standard intake and exhaust systems. By 1972 U.S. carmakers quoted power exclusively in SAE net hp. The change was meant to 'deflate' power ratings to assuage the auto insurance industry and environmental and safety lobbies, as well as to obfuscate the power losses caused by emissions-control equipment.

SAE net ratings, while more accurate than gross ratings, still represent the engine's power at the flywheel. Contrary to some reports, it does not measure power at the drive wheels.

Because SAE gross ratings were applied liberally, at best, there is no precise conversion from gross to net. Comparison of gross and net ratings for unchanged engines show a variance of anywhere from 40 to 150 horsepower. The Chrysler 426 Hemi, for example, in 1971 carried a 425 hp gross rating (often considered to be underrated) and a net rating of 375 hp.



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<font size=-1>[ This Message was edited by: FEandGoingBroke on 3/16/06 4:45am ]</font>
 

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I would guess a factor of .75-.85 would get you in the ball park (15-25% less). I.E. A 325 Bhp would = Approx 260 by todays methods
 

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Discussion Starter · #15 ·
But the motor is not stock... The cam is bigger than the original 325 and the intake valves have been ground to ease flow into the cylindars, and the motor is now a 400 rather than a 390CI.

and...


I can take 80HP off the original 325 and come up with 245 estimated HP, (an estimate of today's specs) which means that, according the the 350 at the flywheel from one estimate I've received I am up by 5 HP (factory), and the 2 estimates from here at 260'ish and 275-300 HP (factoring int the equasion's the 80 hp loss from the factory specs to today's specs...), put's it respectively rated at 340 and 355-380 BHP if it were a "factory" rating.

I suppose what I'm saying is that if the factory made the engine originally with the specs I made this one to it would have rated from 340 BHP to 380 BHP.

So in essence the build on this motor-(being balanced but not blueprinted, factory tests were both I take it) it is still somewhere in the area of it's stock HP rating plus a largest possible overestimate of 80 HP over stock if they were still rated that way. (I am trying to be able to put it into words my 66 year old father can understand... 345 new, and 260hp now would piss him off terrible)

In another sence... What will 10 cubes and a slightly higher than stock cam give this motor?

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<font size=-1>[ This Message was edited by: FEandGoingBroke on 3/16/06 5:12am ]</font>
 

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Cam is really mild, 10 CI isn't really going to make alot more power, Still pulling your intake charge thru a really small valve. Reality Sucks !! 260-270 is probably as honest answer as your going to get short of putting it on a dyno or running it at the track and doing some real calculations.

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<font size=-1>[ This Message was edited by: dfree383 on 3/16/06 5:09am ]</font>
 

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Discussion Starter · #17 ·
so 260 + 80 = 340 which means it has right about 15 more HP than stock if we were looking at it that way, right? Stock HP being 325 - 80 = 248 HP (estimated loss from Factory rates to today's rates) , which translates to 248hp, (If the Caddy was rated post 1972 SAE HP ratings)

Anyhow... I can just tell him that going Sixty over on the bore, tri-angle grind on the intake valves, and a mild cam gave him about 15 HP...
Am I correct in that assumption?

THanks for all the good thoughts by the way...

FE
 

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Agian not having hard performance #'s to back it up? If its not tuned right it could only make 150hp !! Take it to a track, run it and weigh the car and post it, you'll get a correct actual HP answer with that information. But hey an extra 15hp sound like a winner to me....
 

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Thats alot of metal to move !! LOL
 
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