Small block to big block trans cross member doesn't work after swap?

So I purchased this car with out an engine. The trans was still installed. It was a small block 727. So I took my motor home big block 727 and had it rebuilt and used the tail shaft off of the small block trans.

When I go to bolt it up, the cross member only goes one way, but the body of the trans/bell housing hits the firewall and the tail end of the trans is tipped too far upward to get the driveshaft on, let alone in operating position.

I loosened up the two bolts that hold the round rubber mount to the trans and that gave me a little play, but it's still not close. The round rubber mount comes off the transmission and angles back towards the tail end.

So take a gander at the photos, what's not right? The cross member will only bolt up one way, so that's not adjustable, and the round rubber mount is already angled the direction it would give me the most clearance. I've read all the cross members were the same so what gives???

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