73+ Motor Mounts and front xmember on 66 frame

[PapaJbbq]

I've put a 76 front crossmember on my 66 frame. Since the 76 frame rail is taller & narrower than the 66, the engine mounts didn't line up; I notched the frame's top rail and added a 5/8" spacer on top of the rail under the mount to use the original holes. The 350 motor dropped right in with clamshell mounts, but the 700R hits the trans hump seam. I can't get the carb level.
I'm thinking I can take the 5/8 spacer out, and drill a couple new holes in the xmember for the bottom of the mounts.
Before I pull the motor back out, will the clamshell line up with the mounts after I move them?