First - nothing that reads "bolt on" bolts right on, and nothing "out of the box" performs as well as if it´d been fine tuned. Look at the poular AFB-clones by Edelbrock, out of the box, they may be performing good, even satisfying to a point, but sure not perfect and truly flawlessly without some fine tuning.
Second:
-
Idle mixture (needle) screw is located on pass. side carb body, just above the carb flange.
-
throttle stop screw is on the throttle lever, and usually rests on the throttle stop just behind the spark control valve.
Further, on the throttle lever there is one arm standing off awkwardly with another screw, that´s the
fast idle screw, usually close to the
fast idle cam
Ok so far... on we go:
For Convenience, we start with accelerator pump adjustment. Completely close throttle plate by backing out fast and slow idle screws. The lower "HI" position on acc. pump arm is for operation in ambient temperatures below 50°F, for operation at temperatures above 50°F and/ or above 5000 ft. altitude, use the higher "LO" hole o the lever.
Measure distance between roll pin on acc pump lever and pump cover. Stock specs for `65-`67 170-200ci engines was 3/16â€, both manual and automatic transmissions, for 240cid six = 13/64â€
`68 and `69 had 5/32†roll pin/pump cover distance for manual transmissions.
To warm up engine, turn the idle mixture needle screw in so it is lightly seated, then back out 1-1½ turns, then turn throttle stop screw 1½ turns in from where it contacts stop on carb body.
Turn on headlights to place alternator under load, if you´ve got an auto tranny put it in D.
Turn on AC for at least 20 minutes.
With the engine running at normal temperature, adjust throttle stop screw for correct hot engine RPM (check with tach). Depending on Application, that’s 500-575 RPM for manual transmissions and 600-700 RPM for automatic transmissions. Still got the tag on the carb body?
Anyways, turn in idle mixture screw until engine RPM begins to drop from lean mixture, then back out again, raising RPM until it drops again from rich mixture. Turn in again for highest RPM and smooth idle. Check idle speed with tachometer again.
After hot idle speed adjusted, place fast idle adj. screw on highest position on fast idle cam and make sure it stays that way throughout this adjustment procedure. Check specified distance between choke plate ad air horn (pulldown position) with drill bit or feeler gauge: usually 5/32†for 200 auto tranny, 9/64†for manual tranny. close choke plate manually to pull-down position, then release again so it will position fast idle screw on fast idle cam. Check for specifications, if necessary rotate fast idle cam to align fast idle adj. screw with reference mark on fast idle cam and adjacent to shoulder of highest step on cam. With engine at normal running temperature, adjust fast idle screw for correct fast idle speed (1300 – 1500 RPM, depending)
To adjust choke unloader, hold throttle plate wide open, while choke plate is in closed position. Measure distance between plate and air horn, it’s a 1/16†for all years and applications. Bend tang accordingly. Confused yet?
Well, I was, when I did this the first time.
To adjust anti-stall dashpot (often mistaken as “second acc pump“), turn dashpot adjusting screw in until it contacts diaphragm plunger. Turn 2 – 3 ¾ additional turns, depending on how slow the engine returns to idle speed after deceleration.