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Piston speed, Displacment vs HP?

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Old May 8, 2006 | 12:45 AM
  #41  
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Who would care to destroke anything though? Big Bore is what is giving you the extra airflow and big stroke is lowering the rpm for any given amount or power so this is the combination that's both most powerful and most reliable.

Big bore short stroke is stupid for anything other than racing where they don't allow large engines for the express purpose of limiting power not increasing it.
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Old May 8, 2006 | 01:22 AM
  #42  
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Originally Posted by Old SStroker


So do you prefer the big bore or long stroke 408 now that you heard a few varying opinions and some basic physical facts? Inquiring minds want to know.
The thread was never about me though.... it started with a question i had in mind to determine whats best for my setup and also help others to make a decision later on.

In my case my setup is a D-1SC running 15-16psi +50-100 shot of Nitrous. I need to take the engine up to 7100 RPM to max out the D-1SC with a 3.4 pulley. So looking at everything said in this thread and the setups listed above while keeping cost around 5K the Big Bore 396 cid setup with ET 245's heads looks promising. The Nitrous is going to make up the loss TQ from running a 3.622 stroke while the big bore allow for large valves to run great above 7000 RPM.

Another safer and i think cheaper choice after factoring in the heads cost (AFR 205's or ET 215's instead of ET 245-265's) would be going with a 402 LS2 or 408 LQ9 setup, but Im not really sure about taking a 4.00 Stroke that high in the RPM range.

A 4.00 Stroke at 7100 RPM would be running at 4733 PS while a a 3.622 at 7100 RPM will be running at 4286 PS. Im not really sure how the 4,00 Stroke will handle that much PS and for how long?
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Old May 8, 2006 | 02:05 AM
  #43  
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Originally Posted by racer7088
...Big Bore is what is giving you the extra airflow and big stroke is lowering the rpm for any given amount or power so this is the combination that's both most powerful and most reliable...
Big both ways, good for reliable street use, that's what we like.
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Old May 8, 2006 | 02:08 AM
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Is it enough to look at mean PS, or should peak PS be also considered (peak PS can be almost 2x the mean PS in some cases)...?
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Old May 8, 2006 | 07:08 AM
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Originally Posted by LSs1Power

A 4.00 Stroke at 7100 RPM would be running at 4733 PS while a a 3.622 at 7100 RPM will be running at 4286 PS. Im not really sure how the 4,00 Stroke will handle that much PS and for how long?
LS7 has a 4.00 stroke and a 7000 rpm redline. It's OEM built to run a LONG time. Note that GM kept reciprocating parts light and used titanium con rods.

If you aren't thinking light for those parts think VERY strong. No matter what the PS, heavy parts cause more loads.

FWIW, 15 psi and a 100 shot on a 400+ LS with decent heads is probably a TON of hp, maybe 800+??. You might consider the 6.0L iron block and something other than a stock 3.622 cast crank. I can't imagine this blown engine being built for $5K and having any kind of life if it's run in anger, especially at 7000.

Good luck with it!
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Old May 27, 2006 | 07:55 PM
  #46  
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We will try

3.622 stock crank, bring 100 shot on above peak torque @ 5500 rpm. I think we could make 850. 7200 or so. Anyone think the stock crank would break?
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Old May 27, 2006 | 08:22 PM
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Originally Posted by Old SStroker
FWIW, 15 psi and a 100 shot on a 400+ LS with decent heads is probably a TON of hp, maybe 800+??. You might consider the 6.0L iron block and something other than a stock 3.622 cast crank. I can't imagine this blown engine being built for $5K and having any kind of life if it's run in anger, especially at 7000.

Good luck with it!
There are more than one shop that sell a shortblock to handle 1000HP for less than 5K such as Speedinc and HPE.
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