crank pulley bolts replacements

[derrickmd18 at verizon.net (Derrick Floyd)]

 I have to remove the crank pulley and install a new one with a crank trigger ring.  while I'm in there I going to replace the 4 Allen head bolts since I have to take them out anyway. plus the heads are stripped.  I'm looking of or a size to buy because once I take the pulley off I can't drive to the store and get bolts so I need to know the size before hand.  I'm looking for 6 sided bolts.  thanks in advance list.