Engine Timing Driving Me Nuts

[ACK]

A while ago, my 4.1L was stuttering at low RPMs, so one-by-one, I did the following:

- New spark plugs
- Vacuum test
- Rebuilt carb, took apart 2nd time and recleaned again
- Replace ignition coil
- Remove inline fuel filter (has a new one in the carb)
- Went to clean inside of the distributor and found it has a Pertronix, so regapped plugs
- Replace vacuum advance and vacuum hose

Finally, I purchased a timing light with an advance. I marked TDC on the pully and found the timing was completely off the charts, so confirmed TDC again and once more after that. I've been adjusting the timing for over a week and having no success. I slowly pull the timing back, adjusting idle as I go, and when it's around 12 - 18* it doesn't run well at all, it needs a real high idle to keep from dieing and when revving the engine, it sounds like the vacuum is sucking in a whole lot of nothing then dies.

Right now, timing's set at 38* because anything higher seems crazy. Also, when I hook the vacuum advance back up, there's no change in timing.

At 38*, if I'm driving on flat surfaces everything is fine, but it pings going up hills and has no power. If I advance it further towards the original crazy high position, I have no problem with hills, but it stutters in the lower RPMs. I want to replace the current distributor with a HEI to see if it fixes the timing issue, but before I do, is there anything else I should look at to get the timing in line or is there much bigger problem?