[Greasey Harley]

Update:
I have successfully built a Quadra-jet That idles nice about 700RPM, has zero off idle stumble a broad power band and a seamless secondary transition.

I gotta hand it to Cliff over at cliffshighperformance.com . That guy knows his stuff.

stock Q-jet off a 1979 K10 #17059201

Recalibrated Carb specs:

upper Idle air bleeds ------- .695
lower idle air bleeds ------- .075
idle tubes ---------------- .036
idle restrictions ----------- .052
main air bleed (air horn) -- .0845
idle screw holes ---------- .089
acc. pump discharge holes - .028
fuel inlet seat (no window) - .135
primary jets -------------- 74
primary Rods ------------- 50c
Secondary rods ---------- .057 (DR)
Float level ----------------- 9/16 (Set lower for off road)
APT adjusted per Lars Grimsurd's instructions, APT spring provided by cliffs High Performance.
Secondary air flaps notched for smoother transition, secondary tension spring set to 7/8 turn, .
Modified for electric choke

Tested and adjusted it on my 75 blazer 4x4 :

1987 350 TBI block
72cc Swirl Port TBI Heads
Cast Iron GM Manifold (modified to fit tbi heads)
RV Cam
Factory style HEI ignition
initial timing 13*
total advance not including vacuum advance, 34*
50* total with vacuum advance plugged in
4-speed sm465 Trans 4:10 gears and 32 inch tires

Runs sweet
It is going on basically the same setup, except with flat top pistons, 9.25:1 Compression instead of 8.75:1, and 3.73:1 gears rather than 410s