In my Challenger I had the hemi in the stock location on shumacher mounts without a problem. I slightly notched the passenger side valve cover but eveything else, including hooker s/c 2.1/8 headers fitted without a problem.

I guess if you really want to get it centered you'll run into problems with the firewall and trans tunnel. With my 4-speed the bellhousing already was very close to the firewall / tunnel, would not be able to move it an inch.