Drill/tap for sidescrews in a different place. Go ahead and tap for 1/4-20, the stock 6mm strip out easily.
I used 2 short pieced if 1/4 x 1 steel strap, drilled to bolt to the engine, from side to side, and drilled and tapped them for 1/4 bolts to bolt the straps to the plate. Have to use 1/4 spacers between the plate and straps to clear the engine bolt heads.