femtnmax
Well-Known Member
432 engine. 5200 foot elevation. Heat crossover blocked under intake manifold. Mopar OEM style vapor canister in fuel line between mechanical fuel pump and carburetor.
Primary jet .107, second jet .104, meter rod 7547 with pink rod springs to go with 14 inches manifold vacuum. If 10-12 inch vacuum go with original orange spring. Secondary air door 1¼ turn on the tension spring (factory setting). Accelerator pump nozzle .038 (factory is .035), with Link to pump plunger showing "S" shape when viewed from front of carb. Float setting 7/16 with 1 1/8 float drop (both factory settings). Idle mix screws out ¾ turn. A square and ½ of the transfer slot showing with throttle plates closed to idle setting.
Widened the idle circuit transfer slots from the out-of-box .029 inch width to .031 inch. Hand cut with drill bit in pin vise… it cuts quickly so doesn’t take much effort to work up/down the slot. This eliminated a slight lean surge at 1500-2400 rpm.
The .038 accelerator pump nozzles worked well with 3.23 rear axle gear ratio. If any stumble in off-line acceleration try enlarging the accel pump nozzles another 10% to around .041 inch diameter.
If fuel pump pressure is not at least 5 lb the float bowls will have low fuel level with increasing rpm and the engine will stumble.
Air fuel ratios:
Idle = 13
Cruise = 14 at 3000 rpm leaning out to 14.5 to 15 at 4000 rpm
Mild acceleration = 13
Wide open = 12.5
Primary jet .107, second jet .104, meter rod 7547 with pink rod springs to go with 14 inches manifold vacuum. If 10-12 inch vacuum go with original orange spring. Secondary air door 1¼ turn on the tension spring (factory setting). Accelerator pump nozzle .038 (factory is .035), with Link to pump plunger showing "S" shape when viewed from front of carb. Float setting 7/16 with 1 1/8 float drop (both factory settings). Idle mix screws out ¾ turn. A square and ½ of the transfer slot showing with throttle plates closed to idle setting.
Widened the idle circuit transfer slots from the out-of-box .029 inch width to .031 inch. Hand cut with drill bit in pin vise… it cuts quickly so doesn’t take much effort to work up/down the slot. This eliminated a slight lean surge at 1500-2400 rpm.
The .038 accelerator pump nozzles worked well with 3.23 rear axle gear ratio. If any stumble in off-line acceleration try enlarging the accel pump nozzles another 10% to around .041 inch diameter.
If fuel pump pressure is not at least 5 lb the float bowls will have low fuel level with increasing rpm and the engine will stumble.
Air fuel ratios:
Idle = 13
Cruise = 14 at 3000 rpm leaning out to 14.5 to 15 at 4000 rpm
Mild acceleration = 13
Wide open = 12.5
