boring a "94" "8BA"carb base to " EGC " 1 1/16

[Alaska Jim]

I am looking into the feasibility of boring/ honing the throttle plate ( the cast iron throttle body with the butterflies ) on a Holley "94" "8BA" carb to the "EGC" 1 1/16 bore size. Has anyone done this with any success? The reason I ask, is because these EGC carbs are hard to come by up here, and I have a couple of them that the bases are rusted up, and the mixture screws are broken off in them. we have several of the "8BA" carbs that have mangled tops, but the rest of the carb, including the bases are good. Thought that maybe I could make a good carb out of the bad "EGC" if the "8BA" bases can be bored, and not have any problems with any of the other orifices that are bored at an angle into the carb, such as the idle circuits, etc. any body tried this? any success? any ideas, or comments. just trying to make something good out of junk.----- Jim

[Brian]

The larger bores necessitate being machined on different centres, so not gonna work...However, I highly recommend getting in touch with charlieNY on here, he sorted me out with a big bore carb, he's the man!!

[tubman]

I bore out Mercury manifolds to 1 7/16" to match Rochester 2GC carburetors and have the same problem that the bores are not concentric. What I do is have a scrap 2GC base that I bolt to the manifold to use as a guide. I have a jig to mount the manifold on my drill press and use a tool called a Rota-Broach to do the actual boring. The tool is deep enough so it doesn't wander and cuts the bores true. While this works fine for boring manifolds, I don't know if it would be good enough for actual throttle bores in a carburetor, but it would be worth a shot if you have a spare EGC base.

Except for the price of a Rota-Broach (over $100 for an arbor and 1 cutter), it might be worth a try.

[Charlie ny]

I've some of these bases....e mail me if you wish.

Charlie ny

[cmbrucew]

Originally Posted by tubman

I bore out Mercury manifolds to 1 7/16" to match Rochester 2GC carburetors and have the same problem that the bores are not concentric. What I do is have a scrap 2GC base that I bolt to the manifold to use as a guide. I have a jig to mount the manifold on my drill press and use a tool called a Rota-Broach to do the actual boring. The tool is deep enough so it doesn't wander and cuts the bores true. While this works fine for boring manifolds, I don't know if it would be good enough for actual throttle bores in a carburetor, but it would be worth a shot if you have a spare EGC base.

Except for the price of a Rota-Broach (over $100 for an arbor and 1 cutter), it might be worth a try.

Would a fly cutter work? Mill or drill press.


Bruce

[Alaska Jim]

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Sorry about my saying the bore size is 1 1/16, I know that is the venture size, not bore size. sorry about any confusion. I will continue looking around for some parts carbs. locally, and if I can not find any, I may contact the fellows who say that they have some bases, and/or complete carbs for sale. Thank you all for the information.----Jim

[Ross F-1]

Not sure boring will solve the problem, it appears to me the whole throttle section is larger. See photo of 94 base with ECC gasket overlaid.

I have a near-complete ECC 1-1/16" carb gathering dust on the shelf. Let me know if you are interested in it.

[tubman]

Originally Posted by cmbrucew

Would a fly cutter work? Mill or drill press.


Bruce

Probably, if set up right. I do not have these machines and had to make do with what was available. The Rota-Broach works for me because of the depth of the cutter which keeps it in perfect alinement.

[scicala]

I wouldn't attempt to bore an 8BA throttle body to 1 3/8" dia. Just from looking at the picture you can see the bore may run into the seat for the idle mixture screws. Causing another big problem and/or creating scrap.


Sal

[Alaska Jim]

Thanks for all the information you all have given, and all the offers on carbs, all is appreciated. probably will not try to bore it. I will keep looking locally for awhile, before I look out of state. pretty sure I can come up with one, just may take a bit. trying to use the ECG carb as the center carb , on a tri-power set-up on a Y-Block Ford.----Jim