scat 9000 383 chevy crankshaft

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rewguy
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scat 9000 383 chevy crankshaft

Post by rewguy »

what are the outer limits of use on this crankshaft as far as power/rpm go...? I know from a common sense standpoint that maybe 450-500 max hp and 6500rpm is probably what most will say.....but how extreme have you seen? 700hp? 8000rpm? curious........Ive heard stories, but want first hand accounts.
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Re: scat 9000 383 chevy crankshaft

Post by MELWAY »

Not right up there but I pulled one out of a sportman dirt track car,,,500hp 7000revs,,,,did 5 years racing
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Re: scat 9000 383 chevy crankshaft

Post by Modified49 »

i used one in a modified motor and turned 8000-8200 lap after lap with no problems a had a rod let go before the crank did
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Re: scat 9000 383 chevy crankshaft

Post by WeingartnerRacing »

Had a customer I did a set of heads for that made 615hp at 7000rpm. It was still climbing but he didn't want rev it anymore. He has drag raced it for the last 3years.
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Re: scat 9000 383 chevy crankshaft

Post by Blue Malibu »

I have seen the 9000 series cranks last for years running in the lower class at our local dirt track, 425 hp range.
But in the next class up, 500 hp they last about a season and destroy themselves.
On drag race engines they seem to live much longer.

The picture is from one of the upper class engines.
The crank came out in five pieces. :shock:
The customer built the engine himself.
The crank rods and pistons were originally supposed to be for a mild street build but he decided to go dirt track racing instead. We would normally use a steel crank in one of these engines.
It made it through one season and a week into the next.

I will say, I firmly believe it was not the quality of the crank that caused the problem but the fact that he used in in the wrong application.

We have used at least a hundred of the scat 9000 cranks over the years and this is the only one I have seen break.


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Re: scat 9000 383 chevy crankshaft

Post by JWRE »

About 10 years ago a guy came in the shop wanting to get a price on what it would take for me to meet him at the track to tune his engine. The engine had just been built and he had the build sheet with him. According to it, the engine had a Scat 4340 crank and H-beam rods. After looking everything else over and tuning the engine we decided it was time for the nitrous, 300 HP worth. The engine ran great for the rest of the season and then he decided to have me freshen it. When I pulled the pan I couldn't believe my eyes, it had a 9000 series crank and I-beam rods. With the nitrous the engine was pushing around 800 HP. I wouldn't recommend doing that of course, but that just gives you an idea of how strong they can be.
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Re: scat 9000 383 chevy crankshaft

Post by 408 Nova »

600 HP and 7500 RPM for the last three years, no problems. I did have it shot peened though, supposedly increases fatigue strength.
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Re: scat 9000 383 chevy crankshaft

Post by D.Cecere »

I've seen one break into 5 pieces on an engine that made 600hp and 7000rpm.
It largely depends on piston + pin weight and rod small end weight. Light reciprocating parts will be a lot easier on the crank.
The other factor is they are generally externally balanced. Converting to internal balance will definelty help.... seeing that the first place they usually break is the radius between Number 1 main and rod journal.
polishing and shotpeening will also help.
Un-prepped, i would draw the line at 500hp, with a light reciprocating assembly, shotpeening and internal balance you could probably squeeze 600hp keeping RPM under 7200.
With the time and money you spend to improve it, just get the 4340 piece, they're not that expensive and you probably wont break it even if you try.
"Finding horsepower is an addiction"
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Re: scat 9000 383 chevy crankshaft

Post by levisnteeshirt »

Depends how smart you take care of it IMO, detonation would be a no no , Vizard says hes had them way up on N2O, never had one break on a dyno prolly on great gas
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