I am finishing my rebuild on a 350 SB, and I want to make certain I'm on TDC of compression stroke before I do initial startup. I read a tech article on this forum (and used as a guide) that there are two "TDC" and that you want the TDC right after the intake valve on #1 opens and closes. This is where my engine is positioned right now, is this for sure correct? Intuition tells me that it is, but I want to make damn sure. Thanks, Brawley

It does not matter where your engine is for start up. You only need be concerned with the #1 TDC when you are installing the distributor. If you've already gotten past that point then dont worry about it.

No matter which piston is set to TDC, the first one that will even attempt to fire is the one that is ready to begin the intake stroke. Prior to start up, none of them have any air/fuel in them.

That is the correct way, or one of them, for locating #1 TDC. As Kevin said it's only important if you're trying to install your distributor.

I am installing the distributor today, so I was just double checking that I was on the "right TDC" for #1. I can see the head of the #1 piston thru the spark plug hole,the damper is at 0 degrees and I am set on the TDC right after the #1 intake valve opened and closed and both int and exh valves were on the base circle (fully closed) of the cam. Hopefully this is correct. Any other insights gladly welcomed. Brawley

Sounds like you're good to go. Drop your distributor in so the rotor will line up with #1 plug wire in cap. You may have to try different spots before you get the plug wires and vacuum advance can where you want. Make sure you have some room to rotate the distributor, if it doesn't look right pull it and rotate it one tooth and drop it down again. It probably won't drop all the way down because the oil pump shaft won't be lined up. Some guys rotate the engine by hand or kick it over with the starter until it drops. I prefer to use a long wide blade screwdriver to reach down and turn the oil pump shaft to where it needs to be. Now once it's down in there and rotor is pointing to #1 plug rotate the distributor CCW a few degrees before you lock it down. This will give some advance to your timing for initial startup which will help it run cooler while you do the break in.

I dropped the distributor in (after applying comp cams break in lube to the gear) a few times, and used a long bladed screwdriver to rotate the oil pump driveshaft until I nailed it. I used a clear plexiglass distributor cap that I got on ebay to line up the rotor exactly on the #1 plug, rotated it a taste CCW (thanks Hank) and snugged it down. Finally,l replaced the clear cap with the MSD cap that came w/ my distributor. Thanks to everyone for the help. Brawley