big iron ram look that name up on the board. he has a ramcharger about the same vintage with a 5.7 in it.
you can ask him some specifics.

but either way, it seems more expensive right now to add a hemi over a 5.9 mag still, when retaining the efi.

unless you manage to get a complete donor cheap for either one, the stuff to make the hemi work is more expensive.

Also I recall him showing me a place he notched in the frame so the exahust would clear for the hemi. not sure if that is a problem for you or not.