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Old 09-08-2014, 06:27 PM
Bobcat Bobcat is offline
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Join Date: Apr 2007
Cobra Make, Engine: # 757 ERA 427 SC , 482 Al. big block
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Default Drop Base for Holley 4150

I`ve been fighting poor fuel distribution and a carb that just wouldn`t respond to changes like it should for quite a while .
Because of very limited underhood clearance , I couldn`t put just any filter setup on it and the spun aluminum ones were all that would fit . However , the problems with them were insufficient vent tube clearance and a very steep wall behind the element that made the air do some really horrible turns which created a lot of turbulence and other undesirable things ... all of which affected carb tuning badly .
I was talking to a carb man who is one of the best in the country and he said try the Chevy L88 air filter base . Seems he had done a lot of testing and found it to be about the best out there . I did and found that those guys really did know what they were doing back in the `60`s . That base is one of the most efficient units out there , has more drop than the spun aluminum units , correct flow paths ( no steep walls ) and required minimal rework to fit the 4150 .
Basically , just cut off the PCV tube on the bottom and plug it ( hits the accelerator pump arm ) and open up two slots . Clears all linkage and fuel lines and allows me to run a full 3" tall element and have about 3/4" to 1" vent tube clearance to the filter lid .
Carb responds to jet changes the way it should , seat of the pants power is better in all rpm ranges and fuel distribution is where it should be . Car is much smoother at low rpm ( 2200 to 2400 ) also .
All this for about $69 !!
If anyone is interested , I can put up a few before and after photos .
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