Finding TDC Am I wrong?

[Jeffh]

Got into a discussion with some fellows about finding tdc to drop a distributor in on a small block. They were of the opinion you had to either physically see the piston at the top or somehow feel the air coming out of the spark plug hole. I have always just had the valve cover off and if the timing mark was on zero and both valves were closed on cylinder #1 you’re there. That’s the way I’ve always did it but then it’s not like I drop distributors in twice a week. They called BS and that I must have gotten lucky if it worked for me. Who’s right?