#6 not firing!

Ok so I check compression and it was great, 135 on every cylinder. So then I thought maybe a valve was stuck closed, but I have no knocks, or rattles indicating a lifter or push rod bouncing around in there. So I talked to "good ol' dad" (former certified mech) and he guessed at a vacuum leak at that perticular runner since mechanically it was seeming ok. Well I started by spraying starting fluid near that runner (I know not too smart near the exaust and all) and came up with nothing. So then I started digging around and see that there is a vacuum port with 3 plugged ports and one line that leads to the top of the carb. It seemed odd to me that this line went right to the top of the float bowl, but hell Im not the engineer of this carb! So the hose looked like it was in bad shape, I had some more in the garage so replaced it. Get this I start it back up and it runs crappier!!!! That was the only change I made at that point. So I removed the line while it was running and plugged the hole with my finger, WHA LA! it smoothed right out! NO MISS, NO HESITATION! NO NUTHIN'! As I am pondering what the hell the deal is I notice my fingers feel wet and I see there is a tiny bit of fuel on my fingers that has come from the vacuum line I am holding. Well I dunno what the point of that line was but it was sucking raw fuel directly into the intake. So needless to say it is disconnected at the moment and it runs great! I think I need to adjust timing and whatnot because it seems harder to start now but that seems to happen when it gets warm anyway. So I have it solved for now anyway. Anybody have any idea what that line does or is supposed to do? According to the sticker on the fender well it says it is supposed to be there. I hope I can get the hard starting under control because this thing runs like a dream now!