Changing motor mounts with engine in car

'67-72 A-Body Products

look half-way down the page, part number TQA.
They are sold through mancini if i recall.

I installed one in my 66 with the poly loc mounts. Its plenty solid given my TTI's havent kissed my torsion bars yet, and they only have 3/16 of an inch clearance.

This way you wont trash your frame rails and subframe in time as mentioned above.