Rear engine/trans mount holes misalignment

[drfromnc]

Installed my 59a engine in the 34 pickup today but the rear engine/trans mount holes don’t align with forward most set of tapped holes in the frame saddle. They do however align with the center set of untapped holes. Front engine mount bolts are installed using engine mount adapters that are copies of Ford ones. The engine cannot go any more forward or these front bolts will not align.

Is it customary to tap these center holes for the rear mount ?