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Author Topic:   Ford 351w 5.975 vs 6.200
Mike15LM
Dirt Roller

Total posts: 11
posted October 24, 2005 06:11 PM  
what effect on the motor would it have to use the longer rod

dirt_mopar99
Dirt Forum Racer

Total posts: 94
posted October 24, 2005 06:25 PM  
I am by no means an engine guru but by my understanding, longer rods make higher reves and more top end power.

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Speed Kills, Drive a Chevy and live forever!

akadirtracer7
Dirt Freak

Total posts: 217
posted October 26, 2005 10:21 PM  
I,ve been running a 408 with a 6.250 rod and its got alot of bottom end .What ever you run the parts have to complement each other.I had a good mix of parts not to large intake runners it was awesome off the corners but faded on top due to the heads. From what i read the long rod cup motors are the restricted motors.

Normal Sullivan
Dirt Full Roller

Total posts: 39
posted October 26, 2005 11:06 PM  
With everything else being equal, a longer rod moves peak horspower higher in rpm, where a shorter rod lowers torque peak. Not saying that a longer rod, by itself makes more power, just that it moves peak rpm. So it depends on what you're trying to accomplish, whether there's any benefit, as well as what other changes you'll be making to the engine. With a longer rod, the piston stays at/near TDC longer, increasing cylinder pressure, which MIGHT cause detonation, and a long rod motor WILL require a cam change due to decreased intake/exhaust velocities. But if you optimize everything else, a long rod motor will make more HP & less torque (at higher rpm) than a short rod motor of equal stroke

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