my vac advance is bumping into the firewall, whats wrong?  

Are you are saying the distributor body is turning while the motor is running, even if the clamp bolt is tight? If so, pull the distributor and check to see if the rotor shaft is seizing. The shaft should spin with no resistance. If not, pull the shaft, clean and re-lube. Make sure to clean out any oil feed holes or slot in the bushing. I had this happen to my 68 charger with a 318. Hope this helps.  

no, there is no more advance left, maybe i am one plug wire off on the cap ?maybe i have 1 plugged into 8.  

That or maybe you need to restab the distributor but first make sure the oil pump/dist drive gear is pointing at the driver side front intake bolt with engine at top dead center or # piston all the way up.
See your vac advance unit outta be pointing to the #6-8 cylinders or if looking down at it between 8-9 o clock typically.