17084226 mods for Olds 330

[mzbk2l]

Hi all,

I've picked up a stack of mid-80s non-CCC Quadrajets from ebay over the years - mostly 17084226s - after reading from Cliff and others that the design was continually improved right up to the end of production and due to the fact that I needed a TH350 kickdown linkage which was lacking on my original 1967 Qjets.

I've learned a bit about what to look for on a used 80s truck carb either by tearing into them or by mounting them on the car as received.  Some of them have had dual choke pulloffs, some have had single.  I found the front mounted pulloffs to take a little over two seconds to release, while the rears are at or just under two seconds.  Most of them had throttle blades that didn't open to exactly 90°, and some have had power piston retainers that didn't retain properly (found that one out the hard way when the piston popped out during reassembly and stuck the needles out of the hole).  One even had a bent linkage on the driver's side secondaries; it was the part that loops up and hits the arm on the secondary lever for just the first degree or two of travel.  Turns out that loop and arm are intended to provide a mechanical "bump" to start the secondary blades opening in the event that they're stuck in those huge bores.  Spring tension takes over after that, but if your linkage is bent or missing and you don't get that bump, it's very possible for your secondaries to not open.  Learned that one the hard way, too.

Some of the modifications I've made to the one currently on the car:
- borrowed an accelerator pump linkage rod from one of my '67 carbs to take advantage of the clip style so I don't have to drive the pin out of the lever to remove the air horn (ordered several more clip linkages from Cliff so I can use them on the other carbs)
- removed the pressed plug and tapped the air horn for a threaded plug over the APT screw
- removed the front (slower) choke pulloff
- adjusted the throttle blades to open exactly 90°
- made the idle adjust screws accessible
- drilled idle screw holes to .090"
- replaced the power piston retainer
- adjusted the air flap spring to contact plus 3/4 of a rotation
- removed the secondary lockout behind the choke housing

Basically, I've completed the majority of the tips I've read in Cliff's book and on the forums other than changing the metering; that's what I'd like to tackle next.

[mzbk2l]

My questions:
What would be reasonable starting points for modifying the idle tubes, down channel restrictors, jets, rods, and secondary rods, hanger, and/or hanger cam from the stock 17084226 setup?

Current combo:
1967 Cutlass Supreme convertible with a/c and a TH350 and HEI.
Manifold vacuum to the trans and the HVAC, ported vacuum to the distributor.

Olds 330, 9:1 compression (originally a 2bbl)
Edelbrock Performer cam and intake
Unknown vintage TH350 with a fairly tight converter
3:08 rear end
Full dual exhaust through factory manifolds
17084226 carb with the modifications in post #1 above
(fully disassembled, including idle tubes, ultrasonic cleaned, reassembled with 9/32" float height)


I treat this car as a daily driver, so it needs to run and idle in 115° Arizona heat and not go through a tank of gas during a 30 mile freeway drive.  (It already does those things, I'd just like to make any improvements I can while I'm in the mood to play with it.)

[Kenth]

I wouldn´t change much, if anything, using a 17084226 on an Olds 330.
I would however consider reducing the lower idle airbleeds from .078" to .070" and reduce the downchannels from .054" to .050".
Using 9/32" float setting, instead of stock 13/32" gives nothing except worse fuel economy.
Here is the factory recipe:

[mzbk2l]

Thanks, Kenth!