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Old 07-23-2008, 10:40 PM
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SCOBRAC SCOBRAC is offline
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Join Date: Jan 2002
Location: Northern California, CA
Cobra Make, Engine: -Sold- Contemporary 427S/C # CCX-3152 1966 427 Med Rise Side Oiler, 8v 3.54:1 Salisbury IRS, Koni's.. (Now I'm riding Harleys)
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Quote:
Originally Posted by Seaman View Post
I ran the 450's and now have the 600's. The 450's have a mechanical secondary actuation and the 600's are vacuum actuated. I think the 600's are much smoother through the entire band. The 450's seemed to be either on or off, but possibley I just didn't have them tuned correctly. With the vacuum secondaries, you can over size the cfm as the engine will pull only what it needs. Jet it correctly and all is good. I also switched from the progressive linkage to fixed, bringing both carbs in simultaneously. Much better.
Dave

With the 450's A little more progressive linkage will solve the on/off problem. I prefer 1/4 throttle on the front 2 barrels 1/3 throttle gets me most of the front carb, 1/2 throttle gets me 1/3 of the way into the third barrels and 3/4 to WOT gets me all in.

In "race" mode the 450's can be run without the progression and the front and rear carb are doing the same thing at the same time.
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A man that is young in years, may be old in hours, if he have lost no time. But that happeneth rarely. Generally, youth is like the first cogitations, not so wise as the second. For there is a youth in thoughts, as well as in ages... Sir Francis Bacon (1561-1626)
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