• 1/2" x 1" through bolt hole

Shock MNT Holes:

• Strange - 1/2" x 1"
• Afco - 1/2" x 1"
• Santhuff - (1/2" x 1" Standard) 
• Penske - (1/2" x 1" Standard) 
• JRI - (1/2" x 1" Standard) 

Bracket hole dimensions

• 7/8" Wide, Hole centers are 1" Apart