As you can probably guess, there aren't very many 49 year old seasons we can use to compare to
Jamie Moyer's season this year. To be exact, there are only 3. Here they are.
After a 21 year career with a record of 143-122, 227 SV and career ERA of 2.52, 1972 was Wilhelm's last season playing ball. He pitched only 25.1 innings and recorded a record of 0-1 with an ERA of 4.62. Not so great after such a long career.
This was also Quinn's last season in the majors, capping off a career with a record of 247-218 and ERA of 3.29. His final season was not much better than Wilhelm. Pitching only 15.2 innings, Quinn recorded a record of 0-1 with an ERA of 4.02.
Pitching with the AAA Marlins of the International League (affiliate of the Philadelphia Phillies at the time), Satchel threw 111 innings in a combination of 37 starts and relief appearances. The best part is that Paige went 11-4 with an ERA of 1.86 and WHIP of 1.16.
I don't think we can expect such a dominating season from Moyer this year, but don't forget, Moyer maneuvered his 80 mph fastball to a record of 9-9, ERA 4.84, WHIP 1.10 back in 2010.
Power to the semi-centenarians.