Odd fire PRV's have a nifty way to locate TDC #1 (unfortunately not available on 3.0's). It is fast and 100% accurate:
TDC1.jpg TDC2.jpg TDC3.jpg
This is how to do it on an engine with the water pump in place (heater core return line cocks a normal length drill bit over just slightly so it won't slide through the indexing hole in the engine):
Use a 3 inch long 5/16 bolt:
3InchBolt.jpg
Bolt before and after dropping into the index hole (index hole is only about 1/4" deep -- bolt doesn't drop far at all):
3InchBoltOnCounterweight.jpg 3InchBoltInIndexHole.jpg
Using this method the engine will be 100% TDC Cylinder 1 for whatever purposes you may have thereafter.
Bill Robertson
#5939