Here is one way to find Top Dead Center by a tip I got from a guy on Virtual Indian forum:
Message: 22
Date: Sun, 22 Apr 2001 21:07:47 -0500
From: PackardV8@juno.com
Subject: Re: 80 CI ing timing
You can find T.D.C by affixing in a suitable manner a small clear tube to one of the sparking plug hole. Place the other end of the tube in a small reservoir of engine oil. Get the engine near TDC before doing this. Now turn the engine and watch the oil rise and wane thru the clear tube. At the point where it neither rises nor wanes is TDC. This is very accurate too. Then u can affix a degree wheel (somewhere??) to set the timing.
Be sure that on the final turn of the engine it is being turned IN THE DIRECTION OF rotation in order to take up any slack in the components of the engine.