Should it stay or should it go?

Hey guys...opinion question here. I just took the /6 out of my 64 Valiant to rebuild it, but I've been thinking about swapping in a 318 that I can buy in very good running condition for fairly cheap. The question is do I spend time and probably lots more money hopping up the / or go with the v8 swap? And will the 318 bolt up in any way (adapter or none) to a 904 pushbutton? If anybody has any input, it'll be greatly appreciated. Thanks.