While those Northstars are plenty ballsy and have the Cadi bling factor, they are too much of a PITA for this application. All the **** Adam pointed out, plus IIRC the starter is in the lifter valley. Not exactly the easiest engine to work with. Not to mention finding a RWD transmission that will bolt up.
Conclusion: Get some seat time with whatever engine is in it now before tearing apart and spending twice as much as you budgeted on an engine swap