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bodysnatcher (gn24) has one, does it help, who the flock knows. Doubt seriously it does anything for horsepower. Remember, Ford(with the '69 351 W as opposed to all the other Ford's at that time) did it first, then G.M., but both did it because it's easier on the crankshaft, so in that respect, maybe it's worth something for a blower deal. But personally, I can't break the cranks I have now, and that includes 1 stocker 1053 forging. I wouldn't spend one dime more for one, that I do know



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steelcomp was here
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Doesn't a 4/7 swap also have something to do with fuel distribution in the intake? Under forced induction, and with most blower manifold designs, I doubt a 4/7 swap would be of any benefit. Even in the most sophhisticated N/A engines, a 4/7 swap shows minimal returns.
 

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E-7 Sheepdog (ret)
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Doesn't a 4/7 swap also have something to do with fuel distribution in the intake? Under forced induction, and with most blower manifold designs, I doubt a 4/7 swap would be of any benefit. Even in the most sophhisticated N/A engines, a 4/7 swap shows minimal returns.
What I had orriginally heard was that was the beginning of it steel, stopping 4 and 7 from "robbing mixture" supposedly from the ajacent intake runner in some manner, normally aspirated.

Don't think it would do much of anything in a blown setup either.
 

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Cantard
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Discussion Starter #8
Just threw it out there. Give us somethin to talk about. Like I said I know it wouldnt give more power.


OK Back to talking about our rods.:D
 

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steelcomp was here
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What I had orriginally heard was that was the beginning of it steel, stopping 4 and 7 from "robbing mixture" supposedly from the ajacent intake runner in some manner, normally aspirated.

Don't think it would do much of anything in a blown setup either.
On large displacement N/A engines with single four set-ups, especially with small plenum intakes and BIG carbs, there is a benefit.
 

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Cantard
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Discussion Starter #10
On large displacement N/A engines with single four set-ups, especially with small plenum intakes and BIG carbs, there is a benefit.
We did a 377 nos deal and by only changing the cam it picked up 10hp (not a big deal) but sure opened up the torque curve.
 

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Several of my buddies are running a 4/7 swap cam on 1000+ HP roots blower motors. No back to back tests were done so I cannot say if they helped or not. I doubt running this firing order could hurt performance and if there is less crankshaft deflection as a result its worth a few extra bucks in my opinion.
 

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I got one in my 540 the cam grind itself was diff than the first cam,it diid make more power but dont know how much from just swap?I have heard it worth 1 percent.So a 500hp will pick up 5 hp.
 

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Changing the firing order only moves the cylinder robbing from the rear left corner to the front right corner. In my opinion, upon hard acceleration, fuel moves towards the back of the manifold, helping richen up the standard naturally aspirated robbing. Most 4/7 HP gains are from quicker acceleration,like on a car drag strip, not steady state rpm conditions like a jet boat sees on track or on the lake. I have done firing order only swaps and seen nothing in gains on any of my boats or SBFord powered drag cars. Your experiences may vary. TIMINATOR
 
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