Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

Fuel dripping out of primary's

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77cruiser:
OK scratch that. :D

maddogs1965:
One more question for ya Cliff!!!

With some advice from a friend who has two 8 second Camero's , i drilled two 1/8th inch holes in the primary butter fly's behind the throttle shaft (one in each butterfly) is this going to help or hinder me after i receive your manual and do the necessary mods to the carb to make it idle with the cam i am running.

I also noticed  that the main primary shaft is loose as all get out on the carb i am try to tune in. I have a couple of other donor Q jets that the shafts are in great shape. Can i just switch the base plates out and lose the drilled holes, or do i need to remove the un-drilled primary butterfly's and purchase a bushing kit from you and install it?

Cliff Ruggles:
A cam that works well in a 468 isn't going to work well in a 396/402 trying to do the same thing.  CID and true static compression ratio are BIG players in how well any particular cam is going to work.  Using the same cam that works well in some ones 468 in your 396 isn't going to work, it would need to be about 10-15 degrees less duration to act the same way at the same compression ratio, in other words it would act like a LOT bigger camshaft in your smaller engine.

You got bad advice on drilling the throttle plates, that carb has idle bypass air and it is a LOT better to use that system to control throttle plate angle at idle speed with big cams.

Install bushings for the primary shaft, I would NOT install a different baseplate as it's not a good idea with that carb number.....Cliff

maddogs1965:
OK!!!! well it is a little to late to turn back on the cam now  :-\

If i am not happy with the performance, i guess i will be purchasing another one...

I will loose the drilled throttle plates when i install the bushing kit with another set from another donor carb i have....

77cruiser:
Just a thought. Did you degree the cam? What's the cranking compression?
That seems to be a low vac. for that cam I'd expect to see more like 12 minimum.

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