The plates are the best way, less pulling of the engine from the bay, no drilling of the crossmember, and better adjustability. The block bosses are 7" apart, 7/16" hole diameter, the mounting hole is 1.500" centerline to centerline away from the block bosses. I slot the mounting hole about 3" long, 1/2" diameter for adjustability. The slot starts about 2.5" from the front mounting boss of the engine. The driver side needs to be lifted up about 1.25" to level the motor in the engine bay, which I use spacers under the driver side bosses, between the bosses and the plate...
SVT