is a 4 hole spacer bad to use on a dual plane intake manifold?
spacer good or bad?
brl67rs
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NO not at all , that's one you should use with the dual plane.
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2,519 Posts
I would recommend the open spacer for added top end. The dual plane is for bottom end.
What is your combo? Are you pulling something to want so much low end torque?
What is your combo? Are you pulling something to want so much low end torque?
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3,772 Posts
The 4 hole is meant to increase low end torque. The open hole is meant for top end power. Now, you just need to experiment with how large of a spacer to use. I started with a 1/2" and have since moved to a 1". The difference between the 2 was noticeable. I have yet to try the 2", but I imagine there will be an improvement, but I will interfere with the hood. You may be better off with a larger carb. I used to run an Edelbrock 650 Thunder, but switched to, believe it or not, a Quadrajet. Notby far a stock Q-Jet, but a highly modified Q-Jet. I run a Comp 270H(224*/224* @.050" 470"/470" lift) and the Q-Jet produces a TON more torque and power than the Edelbrock ever did. The idle is better, the fuel mileage is better and it allows me to pull farther into the RPM range without falling off. I don't know what they call them, but the Q-Jet is a style of carb that only supplies the motor what it needs at a particular time. My carb is setup to flow 850cfm, but it will only give the engine what it calls for at any 1 time. The later Q-Jets(75-84 non electronic) are very tuneable as far as their part throttle goes. They have an APT screw(Adjustable Part Throttle). It's a screw that adjusts how far the primary metering rods can be pulled into the main jet. With this feature, you can fine tune your part throttle fuel mixture.
Use a 1" 4 hole. When I picked up my 383, the builder (Andy Jensen, http://www.jensensenginetech.com/) dyno tuned the engine making changes and recording the results. The 1" 4 hole did provide the most torque putting it up to 498 lb/ft (with a Holley 650cfm). A 1" open did increase HP, but cost torque.
By the way if anyone in Northeast PA is looking for an excellent builder, check out Jensen's Engine Technologies.
Andy's Camaro
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2,519 Posts
What intake was on this engine?
Tuning with Carburetor Spacers
Carburetor spacers are valuable tuning aids for both performance cars
and racing cars alike. Positioned between the carburetor and the intake
manifold, a spacer will alter the relationship between these two components.
Consequently, the spacer can usefully raise or lower the position of the torque
and power-band within the rpm range. They can also be used to correct
inefficiencies in a mismatched combination. Spacers are available in several
different forms: 4-hole, open, and combination;
they are also made from different materials and in
different thicknesses.
and racing cars alike. Positioned between the carburetor and the intake
manifold, a spacer will alter the relationship between these two components.
Consequently, the spacer can usefully raise or lower the position of the torque
and power-band within the rpm range. They can also be used to correct
inefficiencies in a mismatched combination. Spacers are available in several
different forms: 4-hole, open, and combination;
they are also made from different materials and in
different thicknesses.
4-Hole Spacers.
Generally, a 4-hole
spacer; that is, one with four holes that align with
the four barrels of the carburetor will increase
throttle response and acceleration. It can also
lower the torque and power-bands within
the RPM range. This is accomplished by
keeping the columns of air and fuel flowing
longer, which increases the air velocity.
Adding a 4-hole spacer can be an effective
and practical solution for a vehicle with sluggish throttle response or lethargic
corner exit speeds. In addition, a 4-hole spacer can also help compensate for an
oversized component: a carburetor, camshaft,
intake manifold, etc.
spacer; that is, one with four holes that align with
the four barrels of the carburetor will increase
throttle response and acceleration. It can also
lower the torque and power-bands within
the RPM range. This is accomplished by
keeping the columns of air and fuel flowing
longer, which increases the air velocity.
Adding a 4-hole spacer can be an effective
and practical solution for a vehicle with sluggish throttle response or lethargic
corner exit speeds. In addition, a 4-hole spacer can also help compensate for an
oversized component: a carburetor, camshaft,
intake manifold, etc.
Open Spacers.
Usually an open
spacer; that is, one with a large square-shaped
hole beneath the carburetor, will decrease
throttle response and dampen acceleration. It
can also raise the torque and power-band
within the RPM range, which is accomplished
by increasing the
plenum area.
Adding an open
spacer can be
helpful in overcoming traction problems during
acceleration or corner exit. Furthermore, an open
spacer can also help compensate for an undersized
component: a carburetor, camshaft, intake manifold,
etc.
spacer; that is, one with a large square-shaped
hole beneath the carburetor, will decrease
throttle response and dampen acceleration. It
can also raise the torque and power-band
within the RPM range, which is accomplished
by increasing the
plenum area.
Adding an open
spacer can be
helpful in overcoming traction problems during
acceleration or corner exit. Furthermore, an open
spacer can also help compensate for an undersized
component: a carburetor, camshaft, intake manifold,
etc.
Combination Spacers.
A
combination spacer is distinguished by
being part four-holed and part open and
combination spacer is distinguished by
being part four-holed and part open and
By lowering the torque and power bands
within the rpm range, the 4-hole Phenolic
spacer quickens throttle response.
The open spacer is used to slow
the throttle response, making the
racecar easier to handle on slick
surfaces.
The combination spacer increases
throttle response and acceleration and
tends to broaden the torque and power
band.within the rpm range, the 4-hole Phenolic
spacer quickens throttle response.
The open spacer is used to slow
the throttle response, making the
racecar easier to handle on slick
surfaces.
The combination spacer increases
throttle response and acceleration and
tends to broaden the torque and power
Weiand stealth
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