I have a 67 convertible with a 289 and a 4 barrel holly carb, electric choke. at low rpms, when I give it a lot of gas, the car stumbles and sometimes cuts off. usually happens if I try to accelerate up a hill after a stop sign. Is this a carb issue? I followed a tuning guide I found online and starts with little trouble and usually runs great. I have already replaced the accelerator pump.

 

- make sure that when warm the choke is open (top butterfly at carb)
- start with setting the ignition before tuning the carb:
a) if you have points, check them for gap (dwell)
b) set timing with a timing gun. try (with vacuum advance disconnected and plugged) about 8 degrees advanced at idle

once that is done you might want to check on carb. always ignition first, then carb. golden rule ...

 

I set all of those before I started tuning the carb but I will double check.

 

I adjusted the gap and reset the timing. I could not get it exactly where the manual says but really close. Then I made a small adjustment to the mixture. It runs much better now. There is a small delay when I push on the accelerator but it does not cut off like it used to.

I could only get the timing close because the distributor cannot rotate further clockwise without hitting the radiator hose coming off the engine block.

 

What's your timing set to now?