Intake Port/Polish
More Turbo
Joined: Nov 2003
Posts: 682
Likes: 0
From: Peoria, IL (more or less)
Typically, the biggest gains you will see are in improving what's known as the short-side radius: in other words, the turn where the plenum(s) turns the corner into the runners. Smoothing & blending this area, as well as gently increasing the radius, may help flow & volumetric efficiency. Hard to get more specific without actually standing there looking at the manifold in question. Whether it's worth it is subjective; you may want to look at improving some other areas of the engine as well. Singly they may not do much, but together...
I would not spend any time "matching" the runners to the heads, as long as there is no severe mismatch. If the runners are smaller than the head ports, that's ok, especially on the bottom. This is something of a controversial subject and others may deem it necessary.
Blend the openings as needed to match the carb baseplate, but don't go overboard.
Don't polish anything. Under certain conditions it tends to make fuel drop out of suspension & "puddle" on the walls or floor.
Make certain the carb base gasket & manifold gaskets don't protrude into the openings & trim as needed.
Lastly, I'd gently blend the casting lines in the runners & remove any flash or tooling lumps & call it a day.
Depending on the carb you have & the primary/venturi size, you may actually find that a small 4bbl. like a Holley 390 cfm (1 7/16" primaries) may get slightly better mileage.
I would not spend any time "matching" the runners to the heads, as long as there is no severe mismatch. If the runners are smaller than the head ports, that's ok, especially on the bottom. This is something of a controversial subject and others may deem it necessary.
Blend the openings as needed to match the carb baseplate, but don't go overboard.
Don't polish anything. Under certain conditions it tends to make fuel drop out of suspension & "puddle" on the walls or floor.
Make certain the carb base gasket & manifold gaskets don't protrude into the openings & trim as needed.
Lastly, I'd gently blend the casting lines in the runners & remove any flash or tooling lumps & call it a day.
Depending on the carb you have & the primary/venturi size, you may actually find that a small 4bbl. like a Holley 390 cfm (1 7/16" primaries) may get slightly better mileage.
Posting Guru
Joined: Jul 2001
Posts: 2,119
Likes: 2
From: Southern New Hampshire
If you are running a Holley/Ford 3 bolt 2bbl it may help to put it up on a 1-2" spacer as it will slighty help the higher rpm flow. I run a 2 carb 276" flathead with a pair of 2" spacers and noticed the difference right away.
I dont know if any spacers are available for the later Holley 2300 carb.
I dont know if any spacers are available for the later Holley 2300 carb.
Posting Guru
Joined: Jul 2001
Posts: 2,119
Likes: 2
From: Southern New Hampshire
If you are running a Holley/Ford 3 bolt 2bbl it may help to put it up on a 1-2" spacer as it will slighty help the higher rpm flow. I run a 2 carb 276" flathead with a pair of 2" spacers and noticed the difference right away.
I dont know if any spacers are available for the later Holley 2300 carb.
I dont know if any spacers are available for the later Holley 2300 carb.
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