How do you set timing if starter is dragging?

If the starter is dragging because of a timing issue, the timing is over-advanced. This becomes more obvious when the engine is warm. If it is dragging so bad you can't even start it, retard the timing a little bit and try to start it. If retarding the timing improves the problem, it verifies that it was indeed over-advanced timing. Once you get it running, use a timing light to set the timing to original specs. If original specs are unknown, 8 degrees BTDC was a VERY common setting for the 350, and will most likely work just fine. Don't forget to disconnect the vacuum advance hose if your distributor has one when you set the timing with a light.