Go for it.....it won't run that bad.... will look cool, which is the point. Would look just as cool as another motor that would fit the bill( Flathead V-8), but run much better than that. Those motors make between 130-170 bhp, while yours should be in the range of at least 240-250.
The only other problem I see is the fact that the engine is going in a Merc, instead of a Mopar. Lol.