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question about different carb mounts

jp0863

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havent been working around gas motors in a long time, but will a holley carb work on a spread bore mainfold? switching from the quadrajet to a holley truck avenger, will i have any problems with mounting and running the holley on the stock qj manifold?
 
Not if you get the adapter , and perhaps move the EGR ( mostly for Edelbrocks , I think it clears the holley , but don't qoute me ) .

You can't mount it with out the adapter because 1.) it is not the same bolt pattern spacing , and 2.) the Holley has 4 holes the same size , so unless the carb is elevated a little with the spacer , the primaries can't even open .
 
that makes sense. i need to come up to speed on gas stuff again. used to do all my own work when i had my 67 mustang fastback, now i cant remember crap. i think this is the point in life where one realizes they are older!
 
i just checked my jegs and summit catalogs for the adapter. the only thing i can find is an adapter to mount a spread bore carb on a square bore monifold (lots of them), but not one adapter to go from a square bore carb to a spread bore manifold. what gives? and i'm ditching the egr assembly since i am smog exempt.... just gonna run pcv valve
 
2 ways...

You can simply flip the adapter over,to use it on a Q-jet manifold,and bolt a square flange carb like an AFB on it,it works either way--you could use it to bolt a Q-jet on a square flange manifold as well.....just be sure the correct side is facing the carb,and that the correct gaskets are used,and that they seal 100% of all the bases on both sides..

I've had issues with carb icing when using adapters--they block most of the heat from the manifold "heat riser",and it promotes icing..I had to hook the "EFE" valve up so its buterfly was closed all the time in cold weather,or it would stall every time I tried to let it idle--it would run rich as hell and load up too--lack of heat to the carb might make it faster on a race track,but makes a poor daily driver!..might not be an issue where you live,but here it was the only way I could drive the truck on the streets here,especially if it was rainy or foggy out....my 305 got 3 miles more to the gallon ,and ran much peppier with the heat riser"on", keeping the fuel mixture warm enough to atomize properly..:crazy:
 

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