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Old 03-31-2014, 09:22 AM   #16
Adger Smith
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Join Date: Dec 2001
Location: Texarkana Ark/TX
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Default Re: Ordering New Transmission, but What Gears ?

Terry,
You are right, but he has no real RPM HP he has a torque engine. A 409 will not RPM like a SBC. You have to "work" the engine differently. If you have ever seen a 409 piston and pin you don't want to RPM one of those. Just the sheer weight will take things apart. Right Aubrey? I feel 7,000 is really pushing it. BTY you aren't stealing the thread, you are adding to the discussion.. :~)
If I was gearing a good RPM engine I would go for 8-10% RPM over peak Hp as a shift point and then figure the % gear pull back based on that to keep the engine right around peak HP. I would also work the ratios to get it in high gear somewhere around the 330' on the track.
Sean added a good point about stick cars not having the TQ multiplier of a TQ converter. The old rule of thumb that we used was add at least 20% to the low gear ratio of a stick over an automatic.
My 330 ft mark may be a little early for a stick, but a good automatic will respond to that. It would be interesting to watch a stick Comp car with about the same power to weight ratio as he has and see where it goes to high. On second thought that may not be the real deal because most all Comp cars are 5 speeds. Hummm, might be interesting just to watch!! :~)
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Last edited by Adger Smith; 03-31-2014 at 09:38 AM. Reason: SP & add
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