My WAR calculation is a combination of Baseball-reference and Clay Davenport; I believe it to be the "best" WAR number available for historical comparison. 8 WAR is an MVP quality season. The record is pythagorean adjusted for 162 games.
1891 86-76
C Dick Buckley .6
1B Roger Connor 6.75
2B Danny Richardson 4.05
SS Jack Glasscock .95
3B Charley Bassett 2
LF George Gore 3
CF Jim O’Rourke 1.8
RF Mike Tiernan 5.05
Uti Lew Whistler -.4
C Artie Clarke -1.25
P Amos Rusie 7.65
P John Ewing 4.7
P Mickey Welch -1.5
P Tim Keefe -.95 (28.3) LAST SEASON
-That ends the Giants career of Tim Keefe; he's headed for the Hall of Fame and finishes his Giants career with 28.3 WAR.