Type IV Static Engine Timing?, Stuck in the middle of my rebuild Options

[ThinAir]

I'm really paranoid about making sure I get everything right as a rebuild this engine so after I got the rocker arms bolted down I double-checked the timing. It was quite clear that I'd somehow gotten the distributor shaft off by 90 degrees and I figured that I knew which direction to rotate it so I did.

As I've checked things again, I'm just not sure that I'm not 180 degrees out now that I've repositioned it.

My confusion comes because both 1 & 3 are at TDC when the "0" on the fan is lined up with the case split. Both sets of valves look to me like they are closed at this point, but that doesn't seem right.

So how can I tell from the position of other valves whether #1 is at TDC and on the compression stroke? I know this just got discussed in another thread, but when it came down to actually doing it on the engine it just didn't seem as clear as I expected it to be.

[ThinAir]

Thanks guys! The explanations and the pictures are very helpful. I'm pretty sure I've got it, but I'll use this to check again. One cannot be too careful about such a thing!

BTW - I figured out how I got off by 90 degrees. Because the vacuum pot gets in the way of the bracket nut, I loosen the bracket ring so that I can rotate the distributor to get to the nut. I figure I didn't rotate it back and lock it down again before I removed the distro and the rotation is about 90 degrees. I installed using Jake's video as a guide - using the distributor to make sure the distributor shaft got positioned "correctly" - and it would have if I'd remembered to rotate it back during removal!

Thanks again!