Auto Trans rec for my 5.7 EFI Swap

If you don't want to cut the tunnel, you dont have many options.
A GM 2004R is possible with minimal tunnel work and an adapter. My brother had one built to handle his 500hp 408 in his Dart Sport.
A 518 typically requires more work because its bulkiest right in the crossmember area but some have done it.

The Gear Vendors is the only thing that shouldn't require tunnel work.