Well, Peyton is at the midpoint of his season and he has cooled off a little, but let's see how his current pace stands up to the records cited above.
Current stats (eight games): 237-333 (71.2%) for 2,919 yards (8.77 yards per attempt), 29 touchdowns, 6 interceptions and 119.4 passer rating.
Projected seasonal total: 474-666 (71.2%) for 5,838 yards (8.77 yards per attempt), 58 touchdowns, 12 interceptions and 119.4 passer rating.
Looking at existing NFL single-game records, Peyton's projected final season totals stack up as follows:
Highest passer rating, season (minimum 100 attempts): 122.5, Aaron Rodgers 2011
Highest passer rating, season (minimum 100 attempts), 16 games: 121.1, Peyton Manning 2004. Peyton's current 119.4 rating is close but he will need to fatten up this statistical category with a couple of extremely efficient games to set a new record.
Most pass completions, season: 468, Drew Brees 2011. Current projection [474] will narrowly eclipse this record.
Highest completion percentage, season: 71.23, Drew Brees, 2011 (468/657). Current projection [71.2] is on pace to tie this record. However, Phillip Rivers currently is completing 73.9 % of his passes.
Most games with at least 80% pass completion rate, season (minimum 20 passes per game): 3, Ben Roethlisberger, 2007; Brett Favre, 2009; Drew Brees, 2011. Peyton currently has two games with at least 80% pass completion rate. If he duplicates that feat in the second half of the season, he will break this record with four.
Highest yards per game, season: 342.25. Drew Brees 2011. Peyton is currently averaging 365 yards passing per game, a pace that would shatter the existing record.
Most passing yards, season: 5,476, Drew Brees 2011. Peyton's projected total of 5,838 yards would absolutely shatter the existing record.
Most Passing Touchdowns, Season: 50, Tom Brady 2007. Peyton's projected total of 58 touchdown passes would absolutely shatter the existing record.
Most Games 4+ TD Passes, Season: 6, Dan Marino 1984, Peyton Manning 2004. Peyton currently has four games with 4+ touchdown passes. Replication of that feat in the second half of the season would give him eight such games, which would shatter the existing record.
Best touchdown passinterception differential, season: 42 (508) Tom Brady, 2007. Projected season differential of 46 (58-12) would shatter the existing record.
Best touchdown passinterception ratio, season: 9-1 (36-4) Tom Brady, 2010 (minimum 12 TD passes). Peyton's current ratio is just under 5:1. He will not break this record unless he reels off another long streak without throwing an interception.