Well sure enough, you
can buy a 4L60 to Mopar bellhousing - $1050. At least it is SFI approved.
https://www.holley.com/products/drivetrain/bellhousings/mopar/parts/RM-9071
Looks to need a special flexplate, too? Add another $230.
https://www.holley.com/products/drivetrain/torque_converters/flexplates/oem_flexplates/parts/RM-947
Wonder what a 450 ft/# capable 4L60E would cost? Looks like B&M sells one for $3000
https://www.holley.com/products/drivetrain/transmissions/parts/117308
That leaves $1320 to cover tax and shipping on those parts, plus a torque converter, crossmember and controller and miscellaneous.