Anybody running airgap manifold on a cleveland.its designed for two bbl heads will there be a fit issue for four bbl
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Multiple intakes are "air gap" manifolds.
Do you have a specific manufacturer and part number in mind?
Larry
Do you have a specific manufacturer and part number in mind?
Larry
...This last weekend, Just finished removing the Dual Quads and Installed the Edelbrock 'RPM Air Gap' Manifold #7569, Dual Plane with a 780 cfm, Vac-Secs. I want the Car More Streetable, so I can drive it More.
The Man. ports are 2V and this Manifold fits the 4V heads perfectly, You must use 4V Gaskets. The Manifold 'Miss-Match', forms a 'Shoulder' at the Mating Plane. The gas flow will be faster in the Man. Port until it Slows as the flow Expands upon reaching the Head Port. The Shoulder?...Think, 'Anti-Reversion'.
I have not as yet Fired the Engine as the Ignition is Out being re-built. I will give a report of the Performance in the Near Future.
Removing
The Man. ports are 2V and this Manifold fits the 4V heads perfectly, You must use 4V Gaskets. The Manifold 'Miss-Match', forms a 'Shoulder' at the Mating Plane. The gas flow will be faster in the Man. Port until it Slows as the flow Expands upon reaching the Head Port. The Shoulder?...Think, 'Anti-Reversion'.
I have not as yet Fired the Engine as the Ignition is Out being re-built. I will give a report of the Performance in the Near Future.
Removing
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3 With 'Angle Plate' under carb
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4 Down the Throats, Choke Removed.
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5 I install the Intake Gaskets 'DRY'.
I Do NOT 'Glue' Them in, Nor do I use grease to hold them in place, while 'Dropping' the manifold On. For Those who have Not Attempted a Manifold change on a Cleveland as Yet, this is how you do it. The 4 center holes are unique in that they are Straight-Up Vertical. Install (4) 5/16 NC STUDS 'Finger Loose'!!, The Studs will position the Gasket Exactly, Also, They guide the Manifold as You slide it down onto the Block. This way, The Gaskets will NOT (unknowingly) slip down as You install the Manifold. A Blind Man would get the Manifold Lined-Up perfectly! Once down, Hand start the 3/8" Bolts, THEN remove the studs, and replace with the (4) 5/16" BOLTS! THEN start tightening all bolts in the Correct Sequence. Be advised, on THIS Manifold the Bolt 'Bosses' are Thicker, which will require the use of Slightly Longer Bolts. Approximately, another 1/2" Longer. And Don't Forget, A Washer Under EVERY Bolt HEAD! The SHARP Edge Goes DOWN!! Last, in the past, before screwing in the Bolts, I use to wrap the Threads with Teflon Tape, around the Area that would Enter the Head, to keep Oil from Seeping Out.
I Do NOT 'Glue' Them in, Nor do I use grease to hold them in place, while 'Dropping' the manifold On. For Those who have Not Attempted a Manifold change on a Cleveland as Yet, this is how you do it. The 4 center holes are unique in that they are Straight-Up Vertical. Install (4) 5/16 NC STUDS 'Finger Loose'!!, The Studs will position the Gasket Exactly, Also, They guide the Manifold as You slide it down onto the Block. This way, The Gaskets will NOT (unknowingly) slip down as You install the Manifold. A Blind Man would get the Manifold Lined-Up perfectly! Once down, Hand start the 3/8" Bolts, THEN remove the studs, and replace with the (4) 5/16" BOLTS! THEN start tightening all bolts in the Correct Sequence. Be advised, on THIS Manifold the Bolt 'Bosses' are Thicker, which will require the use of Slightly Longer Bolts. Approximately, another 1/2" Longer. And Don't Forget, A Washer Under EVERY Bolt HEAD! The SHARP Edge Goes DOWN!! Last, in the past, before screwing in the Bolts, I use to wrap the Threads with Teflon Tape, around the Area that would Enter the Head, to keep Oil from Seeping Out.
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Marlin, I got to give you credit. I've installed many an intake and never knew the 4 stud approach. I like it - next time!
I'd like to add 3 comments in regards to manifold design.
(1) The 351C 4V cylinder head has a ramp built into the floor of the intake port, placed there to increase air flow and therefore horsepower. The runners of the Edelbrock Performer intake manifold direct the air stream high, and thus the air stream avoids the intake port ramp as it flows into the 4V cylinder head. Edelbrock's Air Gap manifold on the other hand directs the air stream low, making full use of the ramp built into the floor of the 4V intake port.
(2) Edelbrock's Performer manifold is equipped with an exhaust heat passage, whereas Edelbrock's Air Gap manifold is not. Every 10 degrees F the air temp is lowered shall result in a 1% increase in horsepower. Blocking exhaust heat is normally worth a gain of 20 to 40 horsepower. The exhaust heat passage of any manifold can be blocked, and thus realize the gain in horsepower achieved by reducing air temperature.
(3) Edelbrock's Performer manifold has a full height plenum divider, whereas the plenum divider of Edelbrock's Air Gap manifold is significantly cut down. As fsr as I'm concerned the Air Gap manifold is a single plane manifold that "looks" like a dual plane manifold, with both the low rpm disadvantage and high rpm advantage of single plane manifolds. A person must ask themself which is more important, the peak horsepower number on a dyno sheet or the improved low rpm performance of a "true" dual plane manifold.
I consider the first two items to be advantages in favor of the Air Gap manifold, the third item I see as a disadvantage; I feel the whole reason for purchasing a dual plane manifold is for it to perform as a dual plane manifold; i.e. the time between pulses within the manifold should be doubled. I don't expect everyone to feel the same way, and I certainly mean no criticism of another's choice.
However, I would also point out that if down the road the owner of an Air Gap manifold decided they would prefer it to function as a true dual plane manifold it can be easily modified to do so, via welding a strip of aluminum plate onto the manifold's plenum divider to raise its height. An Australian company named Torque Power sells a manifold identical to the Air Gap manifold except their manifold has a full height plenum divider. This is the manifold sold by CHI to their customers wanting a dual plane manifold. The Torque Power manifold performs great ... even with its full height plenum divider.
(1) The 351C 4V cylinder head has a ramp built into the floor of the intake port, placed there to increase air flow and therefore horsepower. The runners of the Edelbrock Performer intake manifold direct the air stream high, and thus the air stream avoids the intake port ramp as it flows into the 4V cylinder head. Edelbrock's Air Gap manifold on the other hand directs the air stream low, making full use of the ramp built into the floor of the 4V intake port.
(2) Edelbrock's Performer manifold is equipped with an exhaust heat passage, whereas Edelbrock's Air Gap manifold is not. Every 10 degrees F the air temp is lowered shall result in a 1% increase in horsepower. Blocking exhaust heat is normally worth a gain of 20 to 40 horsepower. The exhaust heat passage of any manifold can be blocked, and thus realize the gain in horsepower achieved by reducing air temperature.
(3) Edelbrock's Performer manifold has a full height plenum divider, whereas the plenum divider of Edelbrock's Air Gap manifold is significantly cut down. As fsr as I'm concerned the Air Gap manifold is a single plane manifold that "looks" like a dual plane manifold, with both the low rpm disadvantage and high rpm advantage of single plane manifolds. A person must ask themself which is more important, the peak horsepower number on a dyno sheet or the improved low rpm performance of a "true" dual plane manifold.
I consider the first two items to be advantages in favor of the Air Gap manifold, the third item I see as a disadvantage; I feel the whole reason for purchasing a dual plane manifold is for it to perform as a dual plane manifold; i.e. the time between pulses within the manifold should be doubled. I don't expect everyone to feel the same way, and I certainly mean no criticism of another's choice.
However, I would also point out that if down the road the owner of an Air Gap manifold decided they would prefer it to function as a true dual plane manifold it can be easily modified to do so, via welding a strip of aluminum plate onto the manifold's plenum divider to raise its height. An Australian company named Torque Power sells a manifold identical to the Air Gap manifold except their manifold has a full height plenum divider. This is the manifold sold by CHI to their customers wanting a dual plane manifold. The Torque Power manifold performs great ... even with its full height plenum divider.
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All of the manifolds are firmly in the category of "Industrial Art". The air gap manifolds seem to emphasize that.
I like looking at all of them.
Many of the current production cars have their engines clad to conceal the intakes.
I'm old school. They should be naked.
I like looking at all of them.
Many of the current production cars have their engines clad to conceal the intakes.
I'm old school. They should be naked.