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Edelbrock square bore to spread bore

42K views 15 replies 9 participants last post by  Greg T 
#1 ·
Hey guys i just bought an Edelbrock 1406 and im putting it on my 2101 Edelbrock Performer intake. Will I need an adapter to get the square bore carb to seal right on the intake?
 
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#7 ·
FmrStrtracer said:
This will work, BUT, the picture of the carb you show above is a spreadbore(secondaries are bigger than the primaries.)
That is still considered a squarebore as the center to center bore spacing between the primaries and secondaries is the same regardless of the throttle bore sizes. A true spreadbore has a different center to center bore spacing with the secondaries being considerably farther apart. A 4360 Holley has equal sized primary and secondary throttle bores but the secondaries are much farther apart making it a spreadbore.

I'd use the "adapter" you listed to make sure it seals though, Performer intakes come with one new but they always seem to get lost.
 
#9 ·
Hey guys i was just reading up on the gaskets and I read something pretty interesting. Check this out...

A V-8 engine fires a cylinder every 90 degrees of crank rotation, and the induction cycle of any given cylinder will greatly overlap the induction cycle of the next cylinder in the firing order. The two-plane design isolates each side of the manifold and connects the cylinders in a sequence in which each isolated plenum is connected to every other cylinder in the firing order. Plumbed as such, each side "sees" only every other firing pulse. Rather than having overlapping intake pulses coming into the plenum every 90 degrees as with a single-plane, each side of a dual-plane gets a much cleaner induction pulse every 180 degrees of crank rotation. That's why a dual-plane intake is often referred to as a 180-degree manifold. With the induction pulses coming into the carb every 180 degrees (or actually only one-half of the carb in a divided plenum two-plane), the induction pulse seen at the carb is greatly enhanced, especially at low air speed. This translates to further improved lower-rpm carb booster function and atomization, resulting in better low-end output, enhanced drivability, and economy.

Perhaps the greatest benefit to lower rpm and part-throttle operation with the 180-degree design is that it also largely separates the communication of the induction pulse from the exhaust system. With a single-plane, the wide-open intake valve of a cylinder at peak piston speed on the intake stroke is communicated directly into the plenum, as it should be. At the same time, another cylinder in the overlap phase is also open to the same plenum. At low speed, especially with high-overlap cams, and most acutely at part throttle, this tends to draw exhaust gasses into the cylinder in the overlap phase. This reversion causes rougher low-rpm running and a penalty in torque production until the air speed and overlap tuning effect overcomes the tendency towards reversion at higher rpm. With the 180-degree system, this pathway is greatly reduced, improving idle quality, vacuum, and part-throttle responsiveness.
Read more: http://www.popularhotrodding.com/en...rdcore/0601em_intake/index.html#ixzz1T0ITAb00

So an open square gasket wouldnt seal up the center divider on my duel plane manifold and it would lose those perks it gets from being a duel plane right? Im thinking im gonna get this and trim off any that overlaps into the intakes ports and see how it works.
 
#12 ·
GUITAR1989 said:
Hey guys i was just reading up on the gaskets and I read something pretty interesting. Check this out...

A V-8 engine fires a cylinder every 90 degrees of crank rotation, and the induction cycle of any given cylinder will greatly overlap the induction cycle of the next cylinder in the firing order. The two-plane design isolates each side of the manifold and connects the cylinders in a sequence in which each isolated plenum is connected to every other cylinder in the firing order. Plumbed as such, each side "sees" only every other firing pulse. Rather than having overlapping intake pulses coming into the plenum every 90 degrees as with a single-plane, each side of a dual-plane gets a much cleaner induction pulse every 180 degrees of crank rotation. That's why a dual-plane intake is often referred to as a 180-degree manifold. With the induction pulses coming into the carb every 180 degrees (or actually only one-half of the carb in a divided plenum two-plane), the induction pulse seen at the carb is greatly enhanced, especially at low air speed. This translates to further improved lower-rpm carb booster function and atomization, resulting in better low-end output, enhanced drivability, and economy.

Perhaps the greatest benefit to lower rpm and part-throttle operation with the 180-degree design is that it also largely separates the communication of the induction pulse from the exhaust system. With a single-plane, the wide-open intake valve of a cylinder at peak piston speed on the intake stroke is communicated directly into the plenum, as it should be. At the same time, another cylinder in the overlap phase is also open to the same plenum. At low speed, especially with high-overlap cams, and most acutely at part throttle, this tends to draw exhaust gasses into the cylinder in the overlap phase. This reversion causes rougher low-rpm running and a penalty in torque production until the air speed and overlap tuning effect overcomes the tendency towards reversion at higher rpm. With the 180-degree system, this pathway is greatly reduced, improving idle quality, vacuum, and part-throttle responsiveness.
Read more: http://www.popularhotrodding.com/en...rdcore/0601em_intake/index.html#ixzz1T0ITAb00

So an open square gasket wouldnt seal up the center divider on my duel plane manifold and it would lose those perks it gets from being a duel plane right? Im thinking im gonna get this and trim off any that overlaps into the intakes ports and see how it works.

Take a look at the Air Gap manifold. The divider has been cut down. Best of both worlds, or compromise?


.
 
#13 ·
Hmmm so i went to my local parts store and bought a square bore to spread bore Performer Series carburetor adapter plate for Edelbrock manifolds. Well I just read that this adapter plate works on all all manifolds except two models and one happens to be the one i have :( Im going to call Edelbrock tomarrow and ask them what i should use. Just figured id update you.
Heres the part i bought btw http://www.autozone.com/autozone/ac...delbrock-manifolds-only?itemIdentifier=859488
 
#15 ·
Yeah the Edelbrock rep said the gasket that came with the carb would do fine so i got the adapter and turned out not needing it :p I put the gasket on but im having another problem with the carb now. Its starting up pretty harsh. Im pretty sure its vapor lock so Im going to slap on one of the Edelbrock insulator gaskets and see If that solves the problem :)
 
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