Carb tuning, larger accelerator pump nozzle?
Lot's of different advice but here's what I would do if tuning. A lot of folks will disagree but I know this works at sea level on my motor and your setup is very close to mine.
Get the timing curve setup:
- Pull the distributor and install 1 silver, 1 blue spring. Set total mechanical to 6*. A .059 drill bit will work for the key. Every .010 is approx 1*. Set timing to 27*-28* initial.
- Set the throttle idle screws with a piece of paper. With paper between the screw and stop close the throttle down until you feel slight drag on the paper, open throttle screw 1/2 turn. Set primary and sec the same. Place an index mark on both screws, if you need to adjust idle speed turn both screws evenly.
- Carb setup, IFR .032 IAB .067, PJ 70 SJ 78 MAB .031, EML holes .028/blocked/.028
- Fire the motor and get it up to operating temp. Set the float levels to 1/2 way. Adjust the idle mixture screws evenly (1 full turn is probably where you will be) place an index mark on each screw to keep them even. In nuetral get it to idle around 12.5 on your AFR. People run the idle mixture to lean and the stumble occurs. The IFR provides fuel air mixture to the idle and transition slot, when it's lean everyone throws more pump shot to try and fix it.
- The primary jet and emulsion have nothing to do with the stumble you have. The timing and idle/transition circuit is the problem.
- After you do all this you can dial in the pump cam and nozzle size. Use the least amount of cam/nozzle to accelerate the car.