Pix help a lot.
The front mounts appear new, but are thinner than I would have expected.
As was mentioned, the holes in the mount brackets and holes in the cast iron block are quite generous, so if you loosen the 3 bolts each side, just loosen lower bolt thru long slot of frame, piece of wood under balancer or pan, lift engine till weight off the mounts till they "dangle", use pry bar or similar to shift engine around till in best position. (link above)
The mount holes allow bolts to "wallow" around, allowing you a range of motion before tightening the bolts to block, lower motor till frame mounts touch, pry into best position by the chart posted earlier.
That should improve positioning.
If that doesn't raise it enuff, get some rubber mounts outta mid/late 70s small block p/up truck, or iirc van mounts.
They are about 1/4 inch thicker than car, and I use them often for header clearance.
Shims under the fr mounts is an option, but the truck mounts will prob be best, if the jacking doesn't work.
Keep in touch, you got this.
Good luck