Holley 3811 float adjustment

[William F.]

I don't have the Chevy overhaul manual to look up the float settings for the internal, only, adjustable, floats on the 3811 on my '67 390 hp 427. Can someone give me the space between primary and secondary float and inside of bowl when bowls held inverted for this adjustment? Please specify whether measurements are made at toe end( part of float fartherest away from nedle/seat
) or "heel". I believe specs for primary are at toe and for secondary at heel for some reason.A Holley catalog gives general measurements as 7/74" at toe of primary and 13/64 at HEEL of secondary but don't know if these apply to my stock 3811. Also, what should primary jeting be for this carb only a few feet above sea level?
Thanks in advance.

[Gene M.]

Re: Holley 3811 float adjustment

I've used a .257" drill (no slop, close contact) to set the close end with good results. I feel it's better to favor lean side rather than rich. The more fuel in bowl tends to weigh more. I'm using aviation gas. The spec may be different for front and rear.

[Timothy B.]

Re: Holley 3811 float adjustment

Bill,

My 1967 GM service manual states .170 (3/16) for the primary and .300 (5/16) for the secondary float adjustment. I am fairly certain the adjustment is from the float toe to the bowl with the assembly upside down.

[William F.]

Re: Holley 3811 float adjustment

Tim,
Thanks. Just wondering if you found this in service manual, and if so, where, or overhaul manual? I have the service manual and must have missed it if it's there.

[Timothy B.]

Re: Holley 3811 float adjustment

Bill,

The information is in the 1967 service manual in the back of the book where the specifications are listed.