timing question

You don't just lose timing on a SBF. Something came loose, or something broke. The engine at leat idle anywhere from TDC to 15* or so BTDC. All you have to do is get the static timing somewhere in the vacinity and it should start and run. I would be looking in other areas before fixating on the timing. Pull the distributer and see what the driven gear looks like. Inspect the distibuter and makes sure it spins smoothly, and the advance mechanisms are working properly. Check the cap and rotor carefully, especially inside the towers. If all that looks OK, time to look in other areas: fuel pressure, carb gunk, compression, etc.