Q1.......Set octane to spec (0).
Q2......That is the the actual timing at the "ball" or "mark" on the bell housing, using a timing light. 5 deg BTC Before Top Center. BUDC (Before Upper Dead Center).
Now-a-days it's called BTDC Before Top Dead Center. TDC= When no.1 piston reaches the top of the compression stroke.
Bottom line is: you probably have a UIC, I think that means Upper Center, and the "I" is the hash mark for Upper Center. You don't use that. You set the pointer, that you can see in the hole above starter on passenger side, to point at the BB ball which has a 5 next to it. That's what the pointer wants to be pointing at when the light flashes. (Da Ball). That is 5 Deg BTDC.
You do this with a timing light reading no.1 cylinder firing. Don't take the distributor out.
Re read the manual under timing at 6-19.
"Timing" refers to coordinating the spark, the resulting explosion and the resulting force to be applied to the top of the piston just as it starts down. So it has been decided that on a 216 and all the other motors I know about, you fire just before (in "Advance") it gets to the top and the lag time is such that it blasts and builds pressure after TDC. (beginning of power stroke). If it fires too early, it tries to push the motor backwards, loosing power. If it fires too late, you loose compression, loosing power...and, of course, either way may cause bad noises. This is why you get it as good as you can and then take it for a nice little ride................and floor it.
Then of course your valves have to be "timed" to open and close at the correct time to get gas in, compress and get fumes out.
