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.
1989 – 92-70 NL Champs (d. Cubs 4-1, lost to A’s 4-0)
C Terry Kennedy 1.75
1B Will Clark 9.05
2B Robby Thompson 5.15
SS Jose Uribe 1.5
3B Ernie Riles 1.75
LF Kevin Mitchell
7.9
CF Brett Butler 3.75
RF Candy Maldonado 1.2
3B Matt Williams 1.9
C Kirt Manwaring .05
OF Donnell Nixon -.05
OF Pat Sheridan .65
IF Greg Litton .7
3B Ken Oberkfell .95
OF Tracy Jones -.95
SP Rick Reuschel 3.35
SP Don Robinson 1.9
SP Scott Garrelts 4.3
SP Mike LaCoss .75
RP Craig Lefferts 1.1-The Giants win the pennant for the first time since '62; winning the West, beating the Cubs in the NLCS, then swept by the A's in the Earthquake Series. Clark has the best season for a Giant since '66 and the best season for a first baseman in organization history. Mitchell wins the MVP and has the best LF season in organization history. Thompson has the best second base season in San Francisco history. Speier and Brenly both finish.