8&3/4 Axle questions

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CudaFactHackJob said:
Riiight....$250 plus the markup on the pistons = $1,000. Easier revving??? You can only beat cubic inches with cubic dollars. You picked a bad motor, trans and rearend to start with. Better off to resell that car and start over. Unless it's really a 413; which most 63 New Yorkers were?
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We'll find out. Plus as I recall Chrysler built a 2.2 l that produced 440 horsepower and 440 lb of torque and it was only a 2.2 l
 
And with low compression pistons at 9 to 1 compression ratio for the original low compression 361 at 265 horsepower if I run a turbo giving 12 lb of boost that would be 760 something horsepower so the replacement for displacement is a turbo or a supercharger
 
I can read. I can also do math. Can you? I'm thinking this is your first project car. Learning can be VERY expensive when you don't listen.
 
A turbo that adds 500 hp to a 361... those cast rebuilder pistons are going to have a REALLY bad day. As will the 8.75.
Yeah, my migraine is acting up.
 
Professor Fate said:
A turbo that adds 500 hp to a 361... those cast rebuilder pistons are going to have a REALLY bad day. As will the 8.75.
Yeah, my migraine is acting up.
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Coming man you do know that the compression ratio of a motor decides the percentage per pound of boost, or are you still stuck in the 60' and 70's, a turbo or superchargers amount of added horse power is determined by how much PSI is added to a giving compression ratio, if a 9 to 1 C:R engine has 1 pound of boost added it gains 9% of horse power so if a engine that starts out at 265Hp + 12PSI of boost that 9%gain for each pound of boost so multiply 265Hp*1.09*1.09*1.09*1.09*1.09*1.09*1.09*1.09*1.09*1.09*1.09*1.09=745.36Hp, so at 9to1 CR and 12pounds of boost you get 745.36 horse power on a motor that started out at 265
 
But I'm not adding a turbo I'm giving an example of an archain idea of "there's no replacement for displacement"
 
Read the post. Those cast pistons are going to "exit stage right".
Do what you want, just buy a good broom.
 
And the carburator I am using can't handle the Turbo I have on the shelf
 
Professor Fate said:
Read the post. Those cast pistons are going to "exit stage right".
Do what you want, just buy a good broom.
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Did I ever say I was going to put boost on my 361? I did not my original post was asking if the 741 case can handle the 400-425 HP that the 361 will produce after a overbore of .060 to bring the engine to 372ci for "hot street" use
 
If that beeotch has 3/8 thick cylinders.....that's .375", I'd bore that **** .125 over to a stock 383 bore so quick you wouldn't know what was goin on.
 
225Cuda said:
Coming man you do know that the compression ratio of a motor decides the percentage per pound of boost, or are you still stuck in the 60' and 70's, a turbo or superchargers amount of added horse power is determined by how much PSI is added to a giving compression ratio, if a 9 to 1 C:R engine has 1 pound of boost added it gains 9% of horse power so if a engine that starts out at 265Hp + 12PSI of boost that 9%gain for each pound of boost so multiply 265Hp*1.09*1.09*1.09*1.09*1.09*1.09*1.09*1.09*1.09*1.09*1.09*1.09=745.36Hp, so at 9to1 CR and 12pounds of boost you get 745.36 horse power on a motor that started out at 265
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Boost is related to restrictions in the intake system. You can start at whatever boost you think, port the heads and the boost will drop and the power will go up. Boost is restriction.
 
Rat Bastid said:
Boost is related to restrictions in the intake system. You can start at whatever boost you think, port the heads and the boost will drop and the power will go up. Boost is restriction.
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Boost is actually Relative to the Compression ratio and how much heated air is produce and circlated through a Turbo at 9 to 1 CR with 12psi boost you get a effected CR of 16.06 to 1 and the restiction of the intake manifold is only amplified with the more you push through, the only restriction is the longer the pipe the more you lose, much like a water hose on your house when you put your finger over the end of the hose you are resticting the hose and building pressure behide your finger which is creating a stonger faster stream on the oposite side of your finger from the hose, this is what we call a vinturi effect, OK im done with the science and phisics lesson. But in the end Im not Turbo charging my engine Im just Boreing .060 over for a final Cubic inch size of 372 like the 3rd gen Hemi (which is not really a Hemispherical head) but with wedge heads.
 
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225Cuda said:
Boost is actually Relative to the Compression ratio and how much heated air is produce and circlated through a Turbo at 9 to 1 CR with 12psi boost you get a effected CR of 16.06 to 1 and the restiction of the intake manifold is only amplified with the more you push through, the only restriction is the longer the pipe the more you lose, much like a water hose on your house when you put your finger over the end of the hose you are resticting the hose and building pressur behid your finger which is creating a stonger faster stream on the oposite side of your finf from the hose, this is what we call a vinturi effect, OK im done with the scince and phisics lesson. But in the end I not Turbo charging my engine Im just Boreing .060 over for a final Cubic inch size of 372 like the 3rd gen Hemi (which is not really a Hemispherical head) but with wedge heads.
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I’m not talking about effective compression ratio because that doesn’t make sense. Boost pressure is resistance to flow. Static compression ratio doesn’t matter.

Here is an example. Let’s say you are at 9:1 with stock heads and you have 10 pounds of boost. Same everything but we replace your heads with Trick Flow 270’s and your boost drops to 5 pounds.

What is your effect compression ratio? You have no idea because you are flowing more air at less boost. And you make more power.

All those charts are wrong unless it accounts for port cross section and flow. Boost is a by product of restriction. Reduce the restriction and boost pressure drops.

Compression ratio has nothing to do with how much boost you have.
 
33IMP said:
The weakness of the 741 case is finding r&p for it. The pinion is smaller, but doesn't have the stress risers of the larger pinions. And a 741 uses the exact same suregrips as the other cases. The pinion isn't the weak point in a 8 3/4 case anyway.
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I know Rock auto is not the best place to look for parts , But shouldnt they atleast know which Case came in which car? they listed the axle as being a 742 case but when I pulled it out it is a 741, I say thats bad knowlede on their side of telling me that all 63 Chrysler newport have a 742 case rear axle.
 
Rock auto don't know dick about what is in your car. YOU have to decide what parts you want. All rock auto knows is that somebody might have some part somewhere that you might want, and they can get that other company to ship it to you.
If I can't speak to a human to find out if the part I want is in stock, or speak to a human if there is a problem, that company will never get A SINGLE F#%KING DIME from me.
 
225Cuda said:
Boost is actually Relative to the Compression ratio and how much heated air is produce and circlated through a Turbo at 9 to 1 CR with 12psi boost you get a effected CR of 16.06 to 1 and the restiction of the intake manifold is only amplified with the more you push through, the only restriction is the longer the pipe the more you lose, much like a water hose on your house when you put your finger over the end of the hose you are resticting the hose and building pressure behide your finger which is creating a stonger faster stream on the oposite side of your finger from the hose, this is what we call a vinturi effect, OK im done with the science and phisics lesson. But in the end Im not Turbo charging my engine Im just Boreing .060 over for a final Cubic inch size of 372 like the 3rd gen Hemi (which is not really a Hemispherical head) but with wedge heads.
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Airflow/boost cannot be compared to fluid dynamics, since air/gasses are compressible and fluids (water, in your example) are not (among many other variables). This is why airflow (boost- basically the generation of pressure rated in bar or kPa) is dependent on initial atmospheric pressure (altitude), while closed hydraulic examples generally do not except as a reactionary outside force. Phisics (sic) 101.
 
Dont really want to go off topic but why do the reeds for by Great highland bagpipes are rated in inches of water rather than PSI? the mesurment used is a the discretion of the person doing the measuring, yes liquids are not compressable and gasses are but My example still stands.
 
225Cuda said:
Dont really want to go off topic but why do the reeds for by Great highland bagpipes are rated in inches of water rather than PSI? the mesurment used is a the discretion of the person doing the measuring, yes liquids are not compressable and gasses are but My example still stands.
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Inches of water has nothing to do with PSI. Two totally different things.
 
Well, we're talking apples versus oranges here; For instance; are those V8 bagpipes or Scottish Radial Diesel bagpipes? And everybody knows that water in your bagpipe is a HUUUGE NONO.. Nobody likes the sound of Gurgling Danny Boy..
 
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