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06-21-2023, 11:34 AM | #81 | |
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Join Date: Dec 2013
Location: Minnesota, Florida Keys
Posts: 10,319
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Re: 8ba 275 carb options
Quote:
I used something called a "Rota-Broach" and a guide I made out of 1" thick aluminum to bore the manifold. I just slip the guide over the carburetor studs, clamp the intake manifold on to my drill press, and bore away. The only tricky part is getting the manifold clamped down at just the right angle because the carb mounting surface is not parallel to the block mounting surface. I have done aluminum and cast iron manifolds and they both cut easily. This method allows you to cut all the way down the manifold a full 1 7/16". When this is done, I use a die grinder to smooth the transition at the bottom of the bore. The "Rota-Broach" and it's required arbor are kind of expensive, but I use the in the manufacture of my "trash can" condensers. I have the cutter and an extra arbor I could let you use (along with the guide) for the cost of shipping if you want. All I would need is a $100 deposit to make sure I get it back. PM me if you're interested. EDIT : One last thing. The 2G base has voids cast into it for manifold heat. The size and shape of the Merc manifold carb mounting surface is such that these voids can cause vacuum leaks. This can be remedied by using stacked Merc and Rochester carb gaskets. In the alternative, I have made block off plates made from 1/16" aluminum to take care of this. Since it costs as much to make 20 of these as 1, I have spares. I notice you are in Canada, which may make shipping problematic. Last edited by tubman; 06-21-2023 at 12:00 PM. |
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06-21-2023, 12:21 PM | #82 | |
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Location: East Shore of LAKE HOUSTON
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Re: 8ba 275 carb options
Quote:
Coop |
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06-21-2023, 04:08 PM | #83 |
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Join Date: Dec 2013
Location: Minnesota, Florida Keys
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Re: 8ba 275 carb options
That's the one.
Thanks, Coop. |
06-26-2023, 02:47 PM | #84 | |
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Join Date: Oct 2020
Location: Alberta Canada
Posts: 87
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Re: 8ba 275 carb options
Quote:
also how do you have your choke set up? I'd rather stick with a manual choke |
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06-26-2023, 05:05 PM | #85 |
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Join Date: Nov 2010
Location: NM
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Re: 8ba 275 carb options
From various sources:
Holley 94. Carb. 155 cfm Holley 8ba. Carb. 162 cfm Holley ECG (2110 Y-block) 210 cfm Rochester 1 1/4" flange ("small base"), 1 7/16 Bore x 1 3/32 venturi = 278 CFM.
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'52 F-1, EAB flathead |
06-26-2023, 05:29 PM | #86 | |
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Re: 8ba 275 carb options
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Quote:
As to the difference (if any) from a "Super" dual, I really have no idea. If I had to guess, I'd say that the "Super" would have a slight advantage at speed but would be more difficult to get and keep running right. As I alluded to earlier, there is still a little throttle left on my present set up due to the geometry of the linkage. I adjusted the linkage to get full throttle, which resulted in obtaining a full pull at the penalty of a 1500 RPM idle. The increase was not enough to cause me to upgrade the throttle linkage (yet). I think, given the fact that I have a stock cam, ports, and displacement, the 2G is about all the carburetor my engine will take. I have been a manual choke guy all my life, but the Mercury choke mechanism matched so well with the 2G that it was just too good to ignore. When run backwards, the fuel line and throttle linkage need very little change. The choke however, ends up on the wrong side and pulls backwards and is just located awkwardly. I have done 2G setups with both "regular" (choke mechanism on the carburetor) and "divorced" (choke mechanism located on the manifold) chokes, and all that is needed in either case is a slight bending and shortening of the tube or acuating rod. As a side benefit, I have now learned how to repair and adjust automatic chokes and have come to love them. |
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