help with timing

[dwjack]

I have an ongoing problem with my timing that I would like to finally figure out.
About 4 years ago I bought a 350 from GM part #10067353 and they sold me a balancer part #458652. The timing pointers that came with it are for the 2 o'clock position and the balancer was for 12 o'clock. I made a mark pretty close to TDC and guessed as for timing w/o a pointer.
A little while back I was doing work to my engine and thought that I would finally get everything right. Searching on the web I found the same engine for sale with balancer #6272222. I called the chevy dealer and they told me that this different balancer is the correct one for the engine. So I bought the Dorman version part #594-002.
So anyways, when I checked the timing the way it was set with old balancer it was about 3/4 of an inch before the pointer, with vaccuum advance plugged. I can't believe this is right, there is no way my engine would run decent if it was. When I set it to about 8-10 BTDC it stumbles off the line and runs rough cold.
I'm hoping someone can help me, it would be nice to finally set my timing and know what it is for sure, not just guessing.