Of the few small blocks I have assembled,I have never positioned the distributor according to the timing gear marks !!! This is the first time I've heard of this !
The first time I got my 'head in a jam' over this was on a 440, because I set the distributor in immediately after installing the cam. So I was "confindent," LOL, that the thing would fire right up. WRONG
I first learned the "finger in the hole" trick in the early 70's