To set your valves, roll the engine to TDC #1 compression. Set both valves on #1 (tighten nut untill you have just zero lash, then an additional 3/4 turn). Turn engine in direction of rotation (the way it would turn if it were running) 90 degrees. Set both valves on #8. Turn engine another 90*, set valves on #4. Turn 90*, set #3. 90*, then #6. 90*, then #5. 90*, then #7. 90*, then #2. Try a compression test after resetting the valves, it should come up.
For your detonation, usual suspect is timing, and carbon buildup. If it is timing, set timing to factory spec. If timing is okay, and you suspect carbon, GM makes a kick *** product called Kleens. You set the idle to around 750 RPM, and fog this stuff into the carb, then let it run for 20mins. to 1/2 hour. Then go flog it for a few miles.
For your detonation, usual suspect is timing, and carbon buildup. If it is timing, set timing to factory spec. If timing is okay, and you suspect carbon, GM makes a kick *** product called Kleens. You set the idle to around 750 RPM, and fog this stuff into the carb, then let it run for 20mins. to 1/2 hour. Then go flog it for a few miles.