First let me say than I'm not a Briggs mechanic.
I did a search on the model number you listed and it didn't match anything. As close as I can come is a model 31H707 series 0212 E1
The factory manual for this engine suggests an intake valve clearance of .003 to .005 and an exhaust valve clearance of .005 to .007
Another site recommended intake .004 to .006 and exhaust .007 to .009
I found several generic posts about Briggs crankshaft timing marks. They suggest that there should be a line engraved on the crankshaft BEHIND the crank gear (which is keyed to the shaft)