Where to start?

How do the plugs look? Sounds like possibly a lean misfire. Maybe just me but it seems to me that race plugs tend to foul easier. Strokers generally like 30-32* of timing, why do you have yours set so low? I run mine at 28 initial with 6 degrees of centrifugal advance in by 2000 and drive it on the street a lot. Not enough timing can help foul plugs quicker.

Instead of being a parts changer why not diagnose the problem. If it were mine I'd install a wide band 02 gauge so I could see just what the fuel mix is really doing. I installed one on mine and was astounded at how far the carb was off even though the plugs didn't look too bad