Dear Jack;
If you drill the 1/2" holes in the center it will be fine. The rectangular cut outs are to keep the mounts from turning etc. Just hold with a lg pair of channel locks. Attach the mounts to the engine & then to the crossmember on instlation.
As I recall 55-59 Chev truck linkage works for the gas pedal.
Also when changing the flywheel be carefull not to damage the lock plates for the bolts as they need to be used again.
Good luck, John M....
