Well, if I were to venture a couple of things to try. 1. make sure you have full 12+ volts to the ignition at all times. As mentioned before you may have an ignition problem you assume is fuel related. Also depending on what version of Pertronix it may be causing some grief. There was a version that tried to do multi spark at low RPM. That would probably cause some interesting problems. The Crane is a favorite conversion around here but I'm not sure how sensitive it is about operating voltage. 2. Really need to know you timing setup. Larry's timing setup sticky in the wrenchin' section is really helpful. You really should have at least 14-16+ deg of initial advance with about 34 total. For racing the no vac advance thing is great but for around town the vac advance will help a with drivability and fuel economy. I've been running it on ported vacuum with a limit of about 10 deg additional advance. For reference I'm running right at 10in HG at 850RPM idle in my car. Currently using cam setting 3 but 2 seemed to run about the same.