1965 Front Springs/1965 Holley Carb.

[Joe Ciaravino]

Just bought a set of front springs (standard) for my '65,which are, surprisingly, still available from your friendly(?) Chevy dealer as P.N.:3851100. These springs have a small notch on one end, about 3/4" from the end of the coil, and the coils get progressively farther apart as you approach the notched end. They are identical to the units I am replacing, but I did not take note of these details before removing the old ones from the chassis. Does the notched end install up or down?

What size primary and secondary mainjets, and power valve were originally installed in the Holley 4150 (List 2818-1) that fed the 1965 L76?

[Mark J.]

Re: 1965 Front Springs/1965 Holley Carb.

Joe,

According to Haynes Holley Carburetor Manual, the primary jet is 122-65; the secondary jet is 122-76; and the power valve is 125-65. The Haynes manual is available in the NCRS Bookstore.

Regarding the spring notches, I found it interesting that the Assembly Instruction Manual, Corvette Shop Manual, Chilton's Corvette Repair Manual, Motor's Auto Repair Manual, and Chevrolet Chassis Service Manual DO NOT discuss the notch position. The AIM does state to "assemble front spring with close spaced coils toward frame spring tower."

Mark

[Joe Ciaravino]

Re: 1965 Front Springs/1965 Holley Carb.

Thanks Mark.The closer spaced coils are opposite the notch, thus, the notch must be toward the ground.

Regarding the jets and power valve- the numbers you listed sound like diagram reference numbers. Do you happen to know the sizes of these parts. Are these the numbers I will find stamped into them when I remove them?

Joe

[Mark J.]

Re: 1965 Front Springs/1965 Holley Carb.

Joe,

The jet and powervalve numbers are "part number - jet number." There is also a cross-reference to drill size. For example, your Holley 2818-1 has a primary main jet (122-65) with a drill size .065. The secondary main jet (122-76) has a drill size of .084. There are some Holley experts on the board who may be able to elaborate on the jet sizes.

Mark

[Karl Bugman]

Re: Holley PV & Jet # scheme

Holley jets are commonly referred to by their jet size designation, e.g. 122-73 is a "73 jet" and the side of the jet is stamped with the number 73. Drill size is less important to know than the correct original jet number for a carb and then incrementally tuning from there if need be...

Same scheme with power valves, e.g. a 125-65 Power Valve is commonly called a "65" and will have the number 65 stamped on its side (if it is genuine Holley and you should use ONLY Holley parts on your Holley carb! Not brand loyalty, just problem avoidance.) In the case of the PV, the number indicates inches of vacuum threshold for valve actuation (in this example 6.5"). Here again stock spec for the matching stock engine. On a modified engine use a vacuum gauge to measure actuals and go from there.

[Duke W.]

www.holley.com

Holley has lots of tech info on their web site. 'Course, as a swore AFB devotee, I've never looked at it.

Duke


http://www.holley.com