Thread: Need some carb tuning help

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305 chevy, bascially a stock 84 camaro motor that is now in a jeep - same 3.08 rear, same TH700R4 trans, different carb and exhaust is all.

The carb is a no-number quadrajet(numbers are gone so i know no the year), and got a piss poor 9 mpg and just didn't have the power it should.

I have done the following:
-new base plate (well, used, but known good throttle shafts)
-epoxied up the 6 plugs on the bottom of the main bowl.
-set float to factory specs (was set WAY lean/low)
-set idle mix screws to 2.5 turns out (the were all the way out!!)
-put in pre-74 primary rods - #45 and #70 jets - it had 70s in it, and who know what for rods - they had a step but NO TAPER...hmm. I have post-75 rods i can try - see Q's below
-put in an edelbrock #8 spring in the power piston (have the set...)The old spring was cut down...from who knows what.
-it has no APT (adjustable part throttle)
-adjusted the secondary's air valve spring so they work now.

So it runs MUCH better (around the yard...lights em up easily now, never did before, musch crisper throttle response too)
BUT:
-once started, it idled at 1800 RPM..backed off idle screw ALL THE WAY and still at 900 in neutral, 750 or so in drive. that little tension spring on the idle screw is way loose.
-adding a vac leak causes a rough idle
-closing off the choke a bit improves idle quality. closing the choke will stall it (before the 'rebuild' it would not)

I have no idea if i have a pre-74 carb or 75 and newer. the primary rods a shorter on the newer carbs, and not interchangeable so they say. they will physically fit...but only one will work correctly.

SOOO, the questions are:
-How can i tell which primary rods to use - early or late? (ie identify the carb's year?)

-If my vac leak/air choke tst and brain are syncro'd we are running LEAN...so perhaps the shorter (later style) rods should be tried?

-the power piston spring is the strong one (being a nearly stock engine...) - is this the right one to start with? If too strong, it would make it run lean(er).

Any input folks?

got the idle down - when i moved over the baseplate and linkage over it all appeared the same - the idle screw stop on the new llnkage needed tweaked. it now idles normally, and i checkd for vac leaks and have none.

Soo...have i the right rods?