Its not hard to put in a V8 but certain changes are needed and depending on your access to other "stuff". I despised the crossmember for motor mounts. Buy the ones from JimCarter/Chassis Engineering and make a nice neat clean job. Locate them on the chassis per instructions and that V8 will fit like a glove.
...and yes, I'd plan on moving the steering box outside the chassis and its not that hard either if you follow the instructions from a couple places.
...if you go V8 save your self some time and money by going ahead and putting in a 700R4 Tranny. Take your time and make yourself a neat smooth ride.....and yes, change out the rearend.
Nothing to it

(you can check out my photobucket link for some pics)