No, the heat passage allows exhaust heat to pass under the plenum and warm the fuel mix for better atomization. The heat insulating spacer prevents heat from the manifold from getting to the carb and boiling the fuel in the bowls.
If you are on the street you need to heat passage. The fuelly motors don't have it because the injection is just behind the intake valve. Air gaps are opne plenum high rpm drag racing manifold IMHO.

 

i see yout point now - of course by the same tokin alot of people block off that heat exchange passage.

 

Okay well now I'm sorta leaning toward the street avenger 570...hmmm, well I need to do some more research. When I do this, am I going to need anything other than the manifold and the carb. I mean as far as installation kits and all, what else needs to be replaced?

Thanks everyone

 

all that i can think of is the intake manifold gaskets, a tube of permatex, and a can of carb cleaner would be good to remove any traces of oil/nasty off the gasket surfaces before you reinstall the new stuff.

when installing, be sure you use a putty knife to clean all the old gasket material off the heads. also throw away the end pieces that come in your gasket set (usually cork but sometimes rubber) and instead use a nice 1/4" bead of permatex to seal between the front and rear of the block and your new intake. lastly, use a thin layer of permatex around the water ports on each side of the gaskets to prevent any possible leaks. some people also use permatex around the intake ports but thats optional.

oh yeah, and a little bit of weatherstripping adhesive snotty nasty goopy stuff works great to keep your gaskets from moving aruond on you as you place your intake on top and torque it down.

 

First to the guy from Colorado who is running rich---Any pilot knows that as you gain altitude the mixture richens--Lean it out--As to your question the basics are this ---Any engines performance is being limited by something---Valves?--Ignition?--Displacement?---Compression?---Carburation?----------Putting a Super Duper Carb on an engine which is being limited by something else will not help a bit and may possibly hurt--A stock V-8 Mustang had all the carburation it needs except for possible a .003 ince larger main and/or a more aggresive power valve (maybe)---I would suggest that before anyone makes changes for performance reasons that they make several stop watch performance checks first. Most likely they will find that the stopwatch does not support their hopeful gut impression---It often did not mine.

 

My engine is far from stock, if that is what you are implying...

 

Dan, consider how your linkage is going to hook up to the new carburetor. Not all carbs have the same way to hook up the linkage. Maybe even take your old carb with you- when you buy the new one so not only to turn it in to avoid a core charge, but to compare where the linkage hooks up.

 

That is not the only thing that he screwed up electrical wise. There is so much goofy wiring done to that car. My turn signals do not work, but the shop I bought the car from said he would fix them for free as part of the sale. He gave it a shot the other day, the right one worked fine, but when he turned on the left, it started to catch on fire he said. So a new wiring harness is in my future, just gotta save the money (and get the mrs. to ok it).

 

I'm going to gather all of this information, and talk to my mechanic about it. Ive been going to him for about four years, and he builds race cars on the side. Im sure he knows exectly what my car will need, whenever I get his opinion I will update this thread.

Thanks

 

As far as why some of us don't run Motorcrafts and choose things like Holley instead...many of the Motorcrafts ARE Holleys, Ford never made carburetors, they spec'd them out to carburetor manufacturers.A 4bbl Motorcraft is basically a 4bbl Holley(or whoever manufactured it)that's tailored to what Ford requested. And there are many advantages over using a carburetor that isn't 40 years old in design. Many of the new carburetors have vastly improved metering systems and venturis/boostersthat give you better mileage, better drivability, more power, reduced emissions and increased engine longevity. Also as far as anything bigger than a 480cfm....not everyone has a stock 200hp(if that) 289. Get the right carb for the engine/setup, and there's not going to be a 1 carb fits all. I run a 570cfm Street Avenger on mine, and I get good mileage, good throttle response, good drivability, and it makes a crapload of power for a 302 that operates at under 6k rpm. And the 570cfm is sacraficing top end HP in favor of gaining extra midrange torque and better drivability/mileage. Now, for a stock or nearly stock engine, I agree that a Motorcraft is a VERY good choice because they're spec'd out to what the engine needed(or very near to it) and the tuning is already correct or very close to it depending on if you modified it, and they're also very reliable. But without knowing the flow capability of the heads, and the rom range the cam operates in and knowing what the approximate volumetric efficiency is, it's impossible to spec out the right carb for a car. Might only need 450cfm, might need 850cfm.