We're gonna modify the carb ourselves for the blow through application on the 331 with a vortech supercharger. We want to go with a Holley and wanted to know what size and models to chose from. I don't quite understand the difference between vacuum vs mechanical secondaries but I'll do some reading.
Is this a serious question? Okay - I'll bite on Carburetors 101 Carburetors perform the function of regulating fuel and airflow into the engine Carburetors have from 1 to 4 "barrels" that are more correctly termed venturi chambers - that's why you may see carbs referred to as 1V or 4V carburetors (meaning 1-venturi or 4-venturi chambers) Air is drawn into the venturi chamber(s) by the engine vacuum (created by the intake stroke of the four-stroke engine) Then - by virtue of the 'venturi effect' - the air mixes with atomized fuel (i.e. very small droplets) and flows as an "air-fuel mixture" into the engine (distributed to all cylinders by the intake manifold) The venturis on some 4V carbs are all the same size (like most Carter, Edelbrock, and other AFB types) this is called a 'square bore' carburetor The venturis on some 4V carbs are different sizes (like some Holleys and older Rochester Quadrajets) this is called a 'spread bore' carburetor One set of venturis (usually in the front two) are the primaries 'barrels' - these operate all the time and are responsible for most drive-ability The other set of venturis (usually the back two) are the secondary 'barrels' - they usually begin working at (or near) WOT (wide open throttle) Carburetors with 'mechanical secondaries' use a physical linkage to open the secondary venturis at (or near) WOT Carburetors with 'vacuum secondaries' use the vacuum generated by the engine to open the secondary venturis So that's the difference
I think it's cool as hell to have a Doctor on here working on building his own Maverick. I mean damn I know not all Doctors are filthy rich but I know for a fact that any Doctor worth their weight can afford to just buy a Maverick already restored or pay someone to do it for them. I think it's awesome that The good Ole Doc is out there turning his own wrenches learning how. Especially since he's doing it on a Maverick and not one of the belly button cars
if you think reading mo's posts is great, try working with him. he's like a kid in a candy store. he is very hungery to learn every thing. ill have to be carefull or he will open a store of his own that has a doctors office in the front and a differental shop in the rear!
I as off yet have built a blow thru car......some day....maybe.... Honestly this might be one area where yo have a carb shop build you one... based on your specs..... JMO
Vacuum secondaries use the carburetors venturi vacuum to operate the secondary throttle plates - not engine vacuum.
Cool...I honestly didn't know that. But to beat this horse a little more, how can a carb generate it's own vacuum apart from the engine vacuum...???
do holleys use the venturi vacuum from the primary side? ive never thought about or have been told this fact on vac. secondary carbs.
