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Quick question that I couldn't searching or on google.
But what is the direction that a square bore carb is on a engine for say a V8?
I know most for the inlines will rotate to help with fuel distribution.
Attached picture would be for a V8 as I understand it, is that correct?
Thanks for the help!
The carburetor primary bores face the front of the engine.
On a v8 as you would have each feeding 1 side of the motor but on a straight six you want them to the side (left or right) other wise the front holes will run rich and the rear lean.
It is bad enough they already do that no need to add to it.
To the side you would be like the v8 1 would be feeding the front 3 holes and the other the rear 3 holes.
My .02
Dave ----
On a v8 as you would have each feeding 1 side of the motor but on a straight six you want them to the side (left or right) other wise the front holes will run rich and the rear lean.
It is bad enough they already do that no need to add to it.
To the side you would be like the v8 1 would be feeding the front 3 holes and the other the rear 3 holes.
My .02
Dave ----
An open plenum intake on a 240/300 six Offenhauser "C" for instance, the side of the plenum away from the engine serves the outside cylinders 1 and 6 and the side of the plenum nearest the engine serves the middle two cylinders 3 and 4.
If you face the 4 barrel carburetor's primaries toward the engine, the two primaries will be biased to the short runners for cylinders 3 and 4 and the middle two cylinders will run richer than the outside two cylinders.
We see the center cylinders running richer on the Offenhauser DP where the carburetor has to sit sideways.
The newer Offenhauser "C" intakes have a short divider on the plenum floor to help the flow stay divided between the two sides of the plenum when the carburetor is properly orientated with the primaries to the front of the engine.
An open plenum intake on a 240/300 six Offenhauser "C" for instance, the side of the plenum away from the engine serves the outside cylinders 1 and 6 and the side of the plenum nearest the engine serves the middle two cylinders 3 and 4.
If you face the 4 barrel carburetor's primaries toward the engine, the two primaries will be biased to the short runners for cylinders 3 and 4 and the middle two cylinders will run richer than the outside two cylinders.
We see the center cylinders running richer on the Offenhauser DP where the carburetor has to sit sideways.
The newer Offenhauser "C" intakes have a short divider on the plenum floor to help the flow stay divided between the two sides of the plenum when the carburetor is properly orientated with the primaries to the front of the engine.
Dave
You can run the Carburetor sideways and it will operate as you described if a plenum divider is installed as shown below.
Off idle torque and throttle response will improve as a result.
Thanks guys!
I am working on idea of using lower EFI intake manifold and welding upper intake instead of buying, might not be worth the extra work vs buying one but I enjoy a challenge.
So from what I am hearing I could position the carb in whichever orientation, if primaries are towards engine (on inline) then I would need a plenum divider to divide the primaries vs secondaries.
I might have the primaries and secondaries on opposite sides but either way the idea is still the same.
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