Autolite 4100 SPREADBORE!!
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From: Near Los Angeles
Autolite 4100 SPREADBORE!!
I learned something very interesting today about the 4100: The smaller of the two, the 1.08 venturi, identified by the stamped numbers 1.08 in a clock face to the left of the throttle linkage, on the side of the float bow, which is 480 cfm, that came on engines other than a 289, is a sort of spreadbore. Let me explain.
I was surprised to see that the venturi in the primary bore are 1/8" narrower than those in the secondary bore. Although the butterflies are the same, the venturi restricts, regulates the flow, thus making the carb a 'spreadbore' w/o needing a s.p. manifold.
I like that: having the small primary bores where I do 90% of my driving, and then having the larger secondaries for passing and high school moments. Terrific mpg and performance that Holley paid for for many years still makes the 4100 one of the all time best carbs.
I was surprised to see that the venturi in the primary bore are 1/8" narrower than those in the secondary bore. Although the butterflies are the same, the venturi restricts, regulates the flow, thus making the carb a 'spreadbore' w/o needing a s.p. manifold.
I like that: having the small primary bores where I do 90% of my driving, and then having the larger secondaries for passing and high school moments. Terrific mpg and performance that Holley paid for for many years still makes the 4100 one of the all time best carbs.
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