7" x 3-1/4" x 1/4" thick. 1/2" dia round holes fit the common GM rubber insulator (or the Energy Suspension polyurethane upgrade). 2 are slotted to fit Ford C4, AOD, or C6 trans (or other transmissions with mounting holes on 5-5/16" - 5-9/16" centers). Two are slotted to fit Mopar transmissions with mounting holes 2-3/16" - 2-3/4".