Why do we need so much darned initial static timing?

[davepl]

The BBC in my truck wants, according to the tuneup sticker, (I think) 4 degrees initial with an auto and maybe 0 degrees with a manual. But whatever the actual numbers, 4 is the ballpark. And it'll barely run like that.

Over the on Chevelle forums, where there's a bit more big block stuff going on, the consensus seems to be that most are finding 16 degrees initial is required for best idle, and you then wind up pulling out total so you don't overshoot.

If that's true, great. But as much as old timers complain about "today's fuel", I still don't really know the how and why of us now needing so much more advance. It's not like nitro (very slow burning)!