Somebody in the cracked block thread wanted to see pics of the midplate..here you go. 
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I've got it located by a block bolted to stock motor mounts, and a 200R4 trans on a stock crossmember. I'll weld the mounts for the midplate and then bolt up the 400 trans and make a crossmember for it .
I narrowed the midplate initially by 1.25" on each side. It has loads of room on the passenger side; on the driver's side it needed to be notched on the top edge to clear the firewall seam. I took the BFH to the seam and flattened it for more clearance for a few inches outward from the trans tunnel.
You can see in one of the pics that the top bolts for the trans barely hit. 4 of the bolt holes must be redrilled for the BOP pattern; I located the trans with 2 bolts and the block dowel pins, center punched the holes, and drilled them. No big deal.
The TCI sheet that came with it, written by someone whose native language surely wasn't English, state that to retain the SFI certification, you can't cut the midplate closer than 1 5/8" from the stamped ring around the flexplate, or closer than 5/8" from any bolt hole. With that in mind, it looks like you could put a couple of holes or arcs in it for downpipe clearance.

001
002
003
004
I've got it located by a block bolted to stock motor mounts, and a 200R4 trans on a stock crossmember. I'll weld the mounts for the midplate and then bolt up the 400 trans and make a crossmember for it .
I narrowed the midplate initially by 1.25" on each side. It has loads of room on the passenger side; on the driver's side it needed to be notched on the top edge to clear the firewall seam. I took the BFH to the seam and flattened it for more clearance for a few inches outward from the trans tunnel.
You can see in one of the pics that the top bolts for the trans barely hit. 4 of the bolt holes must be redrilled for the BOP pattern; I located the trans with 2 bolts and the block dowel pins, center punched the holes, and drilled them. No big deal.
The TCI sheet that came with it, written by someone whose native language surely wasn't English, state that to retain the SFI certification, you can't cut the midplate closer than 1 5/8" from the stamped ring around the flexplate, or closer than 5/8" from any bolt hole. With that in mind, it looks like you could put a couple of holes or arcs in it for downpipe clearance.