Here's an easier way (if you haven't already removed the camshaft).

Look at the crank pulley; without turning it, find the TDC mark. Lets call the pointer on the timing cover 12-oclock, since I can't remember exactly what angle...

Wherever it is, move it directly to either 3 oclock or 9 oclock, whichever is closer. Even if you have to turn it backwards. DON'T turn it thru 12 oclock or 6 oclock. Now all 4 pistons are at mid-stroke & you can spin the camshaft wherever you want.

Now position the camshaft to line up the timing marks according to your Helm book.

With the camshaft at the proper position, turn the crank DIRECTLY to TDC, even if you have to turn it backwards. DO NOT turn it thru the 6 oclock position.