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Old 01-22-2004, 09:19 PM
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Secondary needles?

Got a question about different size needles for the secondaries on a Q-jet. I have 2 sets, first set that is from a cutlass and are skinny, and a second set that look to be fatter and were taken from a 305 chevy.

So which needle size would be better for a 305 HO and why?



Last edited by 87442lover; 01-22-2004 at 09:34 PM.
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Old 01-22-2004, 09:55 PM
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GM made literally hundreds of different lettered secondary rods. Each car/engine/tranny/emission combination had a different size and different taper. My experience has been that most times the secondaries are either fully closed or fully open, so the main concern is the actual diameter at the very end of the rod.

My qjet on my 350 has a tip diameter of .056 and it runs very well at WOT.
When I set up my sons qjet for his very stout 400, I used rods with a .040 tip and its way too rich at WOT. I"m going to put in a set of .050 or .056 and see how it goes.

If you have a set in the .050 range, try them. I've seen some in the .060 and up ( huge tip diameter) range but most have been in the small cid smog engines. Those usually also have a limited upper secondary butterfly angle too. I always reset mine to 85 degrees of opening, instead of the 65 or 70 that most are set to.

You can do a lot to a qjet to make them haul and perform very nicely.

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