engine tech

Old 12-31-2007, 07:50 AM
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danweld
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Default engine tech

what are the benefits of a sbc 4/7 swap cam
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Old 12-31-2007, 07:59 AM
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perfconn
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None unless you are using a load of nitrous.Then it will make it a little easier on the crank.
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Old 12-31-2007, 08:49 AM
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us7race
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I have been told that they make the motor run ALOT smoother above 3000RPM like you can't even feel it running. It will also help keep the motor cooler. I have seen the Horsepower guys dyno a motor and pick up 30HP but don't believe that. So in the end my belief's are that it would be easier on the bearings..
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Old 12-31-2007, 05:42 PM
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fishman1
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All what i have read(and read on many posts) on this is by switching 4-7 u have shifted the load to other cylinders and see very little gains if any......so i guess i would say it is all who u talk to u on which way to go
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Old 12-31-2007, 05:47 PM
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jmarksdragster
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BIGGEST BENEFIT IS IT TAKES A LITTLE HEAT FROM 5-7, PUTS THE PAIRED CYLINDERS UP FRONT WHERE THE WATER IS COOLER.
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Old 12-31-2007, 09:09 PM
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Tod74
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You guys are forgetting the main benefit.

They get to charge you more money for them.

Do a search, it was either on this forum or SPEEDTALK that Ed gave a very detailed explanation.
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Old 01-01-2008, 09:13 AM
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edvancedengines
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BIGGEST BENEFIT IS IT TAKES A LITTLE HEAT FROM 5-7, PUTS THE PAIRED CYLINDERS UP FRONT WHERE THE WATER IS COOLER.
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You guys are forgetting the main benefit.

They get to charge you more money for them.
Both of the above are the benefits and who it benefits. Most of the people who are selling the 4/7 swaps only know what they have been told to say to get it sold. Yes' there is a good benefit but that sole benefit is to even out the colling in the cylinders and to take the heat load off the rear driver side cylinders where those two were at the back of the coolant flow path and were firing consecutively.

The 4/7-2/3 sway is different though. IT also aids in the cooling equalization but gives for the easier bottom end loads. Look at it this way. With standard firing order in a Chevy or Mopar You have each rod hamering at the crank to make it turn in large increments like a sledge hammer blow. The more violent the engine is, the more harsh the blow is to the crank rotation which twists with each fireing and power stroke cycle. With the 4/7 swap you still have the same thing except when it is either the 7 or the 4 that is doing it's number and that load is not quite as great. If anything I would think the 4/7 should run a little more uneven becuase of this but in real life it seems to be the same. The 4/7-2/3 sway does smooth it all out and is like a smaller rubber hammer pounding blows to the rotating crank with the crank force with each consecutive blow to be not as extreme becuase of lesser rotation per power stroke force on the crank before the next cylinder takes over.

Feel a 350 engine idle and listen to it run with a regular or a 4/7 order cam. Feel an LS engine idle and run. No comparison in the extra smooth LS engine. That is the sole purpose and logic behind the 4/7-2/3 swap called a C Swap. The Chevy Engineers were wanting to do something to give a better longevity with the lower end of the new designed LS engines. The engineers talked with Steve Lowe Sr about their ideas and consulted in his opinions. The rest is history.

Want to know why so many cam companies and builders dedicated to them are now saying the 4/7 is the best ticket? They can not get the cores to make the C swap cams except in a very few applications like is used in Cup type Racing. Cam Motion has a very few capable cores to do a C-Swap. Only LSM System Engineering and Crower Mfg are making many different available cores to do the C-Swap.

Everyone and his brother now have the 4/7 swap cores.

You may get some slight additional power increases and you may not.

Ed
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