Originally came with the Briggs 31H777-0297-E1. If your mower still has the original engien you will need the 793880 camshaft, PTO side seal, rocker cover gasket (or RTV) and the oil pan gasket.
793880 superseded to 84005207 camshaft (note does not come with tappets)
795387 oil seal
272475S rocker cover gasket or 100100 RTV
697110 Oil pan gasket
You also may need 5/16-18 helicoil kit if you have any stripped oil pan screw holes. I just had to install two these helicoil last week in a 310000 series where they pulled out before reaching the 18 ft-lb (220 in-lbs) torque spec.