Originally Posted by CBinDC
I've noticed when I initially doing the timing everything sounds fine. Its when I reconnect the distributor vacuum advance is when I start to hear the problem. If I disconnect it, I don't hear the sound.
There's your sign that you have too much initial advance. The manifold vacuum is adding too much for that base setting of 8 BTDC.
Every engine is different as far as what the timing marks actually read. Pointers/marks can be off of true top dead center. 8 degrees is just a starting point. Feel free to change it til YOUR engine runs well...then adjust the carb.