For Paw Let's start in the beginning. Do you know the Alt output?? Yes, No, maybe? You need an Alt that can keep all the electrical loads running and keep a min of 12.5 volts going to the battery at 1000 rpms. THE ALTENATOR is what powers all the loads once the motor is started. The battery is for staring the car and backup if the car idles for a long time with everything on,lights, cooling fans, blower motor, Msd module, Msd coil, electric fuel pump, etc. The batttery also absorbs the charging spikes from the ALT. What pulleys are you running? If they are not about 6" in diameter for the waterpump and crank pulley, they are TOO SMALL. The March system is underdriven and is good for racing and high rpm motors but not street driven low rpm cruiser. Here is some facts, MSD module draws about 16-20 amps, the coil draws about 6-10 amps, coolant fans, depending on how many from 10-30+ amps, electric fump pump 8-15 amps, Head lights and tail lights about 8-14 amps depending on what type, heater blower motor depending on speed, about 12-17 amps. With just the 6 thing a have here you are over most alt outputs at idle. An MSD system will not work below 10.4 volts. This is the steady drain on the system. Turning things on and off you are looking at spike loads of double to triple the running loads. This is why your car starts running rough. Not enough juice. A 100 amp min is the standard thing with normal pulleys. Most new car that are loaded are running 200 amp alts.
Your playing with the timing is not helping. What is the CCA, cold cranking amps of the battery?? You should have something in the 800-1000 if possible. If you are going to idle the car for more than a minute or 2. Shut the motor off and just run the coolant fans. Lets a solid lifter motor run at idle is not good for the valve train IMO. Get the right pulleys for the car to start, make sure you have a large CCA battery, and replace the Alt with a min of 100 amp. A 140 would be better and cost about the same. Make sure the MSD system is hooked up directly to the battery for the red and black wires. This should help fix your problems. If you have any questions call me 732-254-3536 in the evening est time Rick Lake. Ps MAD Alt and PA Alt have real easy alts to swap into your car for plenty of charging. You may have to swap your amp gauge to a volt gauge with the power increase. There kits are 1 or 2 wire. Something to look into. Rick