Holley 3810 fast idle cam

[Gerard F.]

Was it white or green? Certain parts places sell an OEM fast idle cam for a 67 carb, as a white plastic cam. Replacement 3810's have a green plastic cam, and a 763 dated one I have (which has been highly modified) also has a green cam. But a 751 dated one I have has a white cam (actually more vanilla yellow with age).

So what should it be, green or white?

[John H.]

Re: Holley 3810 fast idle cam

Was it white or green? Certain parts places sell an OEM fast idle cam for a 67 carb, as a white plastic cam. Replacement 3810's have a green plastic cam, and a 763 dated one I have (which has been highly modified) also has a green cam. But a 751 dated one I have has a white cam (actually more vanilla yellow with age).

So what should it be, green or white?

Jerry -

My 731-dated 3810 has a whitish cam.

[Gerard F.]

Re: Holley 3810 fast idle cam

Jerry -

My 731-dated 3810 has a whitish cam.

John,

How about the bowl vent rod on a 3810. I've seen them black on replacements, but have seen a lot of restored carbs that had a zinc finish on the rod and the spring. On my 751 project I made the rod and spring black. But this 763 just looks like just dull zinc and rusty. But again, it has been highly modified.

[Timothy B.]

Re: Holley 3810 fast idle cam

Jerry, The fast idle cam on the 3810 dated 673 is aged white color. The linkage for the bowl vent is plated.

I received a new primary metering block from holley Thursday and it's the new style with the webbing. no #'s stamped into the top but a #4508-3 engraved into the drivers side vertical very lightly. I need to find some 1/8" stamps so I can stamp # 4743. I am also going to double check the IFR and PVCR hole size. This is a nice metering block compared to the old part, I paid 45 plus 5 for shipping.

I am still not sure if the old block could be used, there is a pic showing the JB weld I tried to use to level the area that has warped. This area can be felt with your thumb so check your metering block, if vacuum finds gas around here from the idle down well, it is sucked into the curb idle hole just under and rich idle..

[Gerard F.]

Re: Holley 3810 Here's my three blocks

Tim,

Here's the three 3810 metering blocks I have:




The one on the left is from a later replacement 3810 1980's-90's and is stamped 4508 with a 3 under, on the top where you would find 4743 on others. This is probably the first design of the one you have, which was a replacement for the 4743.

The one on the top was a brand new NOS 4743 Holley replacement part the I acquired about 5 years ago and used it to replace the 4508 on my replacement 3810. It is stamped 4743 on the top.

The one on the right is the one that came with the 763 carb I'm restoring.
It is stamped 4743 on the top and I believe it to be original the 763 carb.
It does appear to have been worked on the past and has a broked off gasket stud. But it is flat as a pancake:



Note the very slight differences in the castings between the two 4743's on the left side.

I also picked up an NOS 22 metering plate on ebay:



Was $25 and will replace the #19 that was on this 763 carb.

I'm getting into dissassembling this carb, and I'm finding the metering surfaces of the body also flat as a pancake. Looks like some one worked on this carb before as I can't believe a 42 year old body would be without any warp. Looks like I won't need that belt sander or milling on this one but a little touch-up with the sand paper on a plate won't hurt before I recolor.

One question for you. Was the vent bowl rod plated in zinc, or was it black phosphated? The rod on this one looks like it has some remnants of black between the rust.

[Clem Z.]

Re: Holley 3810 fast idle cam

you need to cut your straight edge to the length of the gasket so you can use it to check the flatness of the gasket surface. that is how i check mine using a cut off 6" scale from a machinist square

[Timothy B.]

Re: Holley 3810 fast idle cam

Jerry,

The vent rod on this carburetor is zinc plated but it's been through a rebuilder so I can't say for sure which is correct..

The original 4743 metering block from my carburetor is straight where you indicate with the straight edge but look at the area I explained earlier where the JB weld is shown.

Clem, Would this JB weld hold up to gasoline and have you ever seen one warped in this flat area??

[Clem Z.]

Re: Holley 3810 fast idle cam

Jerry,

The vent rod on this carburetor is zinc plated but it's been through a rebuilder so I can't say for sure which is correct..

The original 4743 metering block from my carburetor is straight where you indicate with the straight edge but look at the area I explained earlier where the JB weld is shown.

Clem, Would this JB weld hold up to gasoline and have you ever seen one warped in this flat area??

the area you have to worry about being completely flat is the area where there is engine vacuum like around the power valve area. that is why these areas have the fine raised areas to "bite" into the gasket. i have used JB weld to repair carbs BUT this was before they added 10% alky to the gasoline so i would try and contact JB weld. i always used the original holley brown or black paper gaskets because they a lot softer than these new "non stick" ones so they will seal any areas that are not completely flat. these gasket are a bitch to remove but they seal.