In the forum archives under timing marks you will see how I did it using a dial
indicator with the head off.
Another way I use to find TDC with the head on is with a ohmmeter
A analog meter works best with a stiff piece of solid insulated copper wire.
Bare both ends of the wire. Connect one end to the meter and connect
the other meter lead to a good ground on the block. Insert the other
bare end in to number one spark plug hole so it will touch the top of
the piston. Make sure the piston is on compression stroke with both
valves closed. (You can check that with you're finger over the plug hole)
Very slowly turn the engine over forward. Watch the ohmmeter. as soon as the
meter shows continuity. STOP Make a mark on the front pulley where you can
see it easily. Continue turning the engine over slowly,
When the meter shows you lost continuity STOP. Make another mark
on the pulley. Dead center between these marks should be TDC.
Do this a couple of times to be sure you have it right.
Mark the pulley and the block there. I used a dremel tool.
You have TDC marked. Now measure the circumference of the pulley
and divide that by 360 deg. That gives you 1 degree, Multiply that by 4
and make a mark on the pulley only BEFORE the TDC mark.
That is where you want the spark plug to fire.
If you're front mount distributer is in good condition and you
static timed it, That is where it should fire.
Incidentally, You can time it on either the no 1 piston or the
number 4 piston. One piston firing the plug and the other piston
finished exhaust stroke starting intake stroke.
Also some side mount engines have 2 sets of timing marks 180 degrees apart.
You can time it on any of the 4 power strokes. One set of timing marks for
1 and 4 piston the other set for 2 and 3 pistons. Make sure you are using
the right set of marks for the compression stroke.