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Author Topic:   Flow numbers
juni
Dirt Full Roller

Total posts: 73
posted February 14, 2002 12:31 AM
Can any body tell me some flow numbers on 283 power pack heads . I am limited to stock bore rodchester 1 3/8 bore cannot pollish it out any bigger than what it came with. My thoughts are that if I can not flow much air that the smaller intake runners would give me more velosity . Or should I use old double humps?..

Donnie Ross
Dirt Maniac

Total posts: 109
posted February 15, 2002 08:28 PM
dont know the numbers if you have the double humps use them, I have to use a set of the powerpacks this year and am not realy expecting great results due to small valves and ports.

Monster
Dirt Maniac

Total posts: 135
posted February 15, 2002 08:46 PM
You are right in thinking that the smaller runners will give more velocity, but there is such a thing as TOO MUCH velocity, that become pumping losses, which means low power. A 355 cubic inch restricted engine making peak torque at about 5000 rpm, peak bhp at 6000 or so, wants a port about 215cc or so, for good torque and power. That means put on the best heads you can find, even with a small carb. Think of the carb as a soda straw.. the more vacuum you pull on it, the more flow(power) you get from it, even though the straw(carb) stays the same size. The better heads will pull harder on the carb.

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