ECZ-G heads w/ edelbrock 573 or edelbrock 553


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By Ghsthrss - 13 Years Ago
So I am currently building a 292 for my F100, I have ECZ-G heads w/ the edelbrock 553 intake, will the port size on the heads match the manifold, or should i hunt down the edelbrock 573 manifold for my current setup. Note that this motor is in a 4x4, not that it will see any more mud than it takes to get out of my drive way in the winter. Is the difference in the manifold going to benefit me in any way?
By NoShortcuts - 13 Years Ago
Welcome to the Forum!



The intake manifold passageway porting is smaller on the Edelbrock 553 than on the Edelbrock 573. The smaller passageways increase the velocity of the air fuel mixture at lower engine rpms. This increased speed of the air fuel mixture can enhance lower rpm engine operation (off-idle drive-ability, lower rpm throttle response) by preventing air fuel mixture separation and providing more of an air fuel mixture ram effect. The ram air effect is a result of the rules of inertia.



At some point when reaching higher engine rpms, the smaller passageways of the 553 intake manifold will restrict the flow of the air fuel mixture. Sooo... for higher rpm operating engines, the 573 will better supply the air flow requirements.



IMO, if you are using your vehicle for street and highway driving, you may well find the 553 performance superior to the 573! Bigger is NOT always better. It's a matter of the engine rpm range that your vehicle operates in.



One caution, check to see how the intake manifold ports align with the cylinder head intake ports. The gaskets have to seal, even if there is some port misalignment. This check can be done with an intake manifold gasket. Likely there are Forum members who have done this installation and will chime in with their experience with this 'mis-matching' of ports.



The Edelbrock 573 seems to regularly bring more money on eBay than the 553.



Hope this helps! Smile
By Ted - 13 Years Ago

The Edelbrock 553 three deuce intake fits the ECZ-G heads without issue.  As noted the ports are smaller at the heads than those of the 573 intake but that makes it a better street driver at the expense of some of the higher rpm attributes.  Here’s the link to the dyno results where several 3X2 intakes were tested.  The second link details the low rpm attributes.

http://www.y-blocksforever.com/forums/Topic40554-3-1.aspx

http://www.y-blocksforever.com/forums/Topic40554-3-3.aspx 

By DANIEL TINDER - 13 Years Ago
I can second that. Small port 4 barrel '55 manifold runs great on the street with Holley teapot through large port heads. No need for port/gasket matching work either if you limited to OEM rev range.
By Riz - 13 Years Ago
To Further muddy the water, everything said is correct, i have a 292 with g heads and the Offy 3x2 running original Holley 94s. It also starts to be affected by cam profile and even the rocker ratios. Basically without a major swap of a lot of parts it is difficult to capitalize on the max potential. It really does matter with the RPM range and also the range of your checkbook. I got the Offy for a song in price and went old school fixing up the 94s. It is definately better than stock, but with 3:89 gears in back and a 3sp AT. I just tuned for low end RPM, the engine is orig. so I keep it to sub 4000 RPM. The 553 and 573 are better intakes than mine, but considering I picked mine up for $120 vs the $800-1000 I see on the edelbrocks, I could use the spare $$ for other goodies and be happy with less HP.

If I were going to tear the engine down, go top shelf on all the guts forged pistons, roller rockers, rods, cam etc to rev to 5000-6000 with out scattering my motor, I would probably spiff for a 573. I always try to think HP per c.i. And HP per $.