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

Minnesota Muscle said
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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Couple things going on here and you need to be very clear about the front end of the trans and where it’s hitting. Also show some pictures of that.
I can see in the third and fourth pictures of your original post that you have a later truck style output housing, the part your insulator is bolted to. I have that same housing and trans crossmember currently installed in my A-body, although mine is a small block right now, and is a later 1975 model year.
I previously had this same crossmember and insulator, and the same driveshaft with my previous big and 727 trans in this same 75 A-body.
I will add a picture of my crossmember, although it’s from a different angle so hard to compare for sure, but shows yours is installed correctly.