What is the easiest to swap into a mazda b

hey guys my engine is about to shit out, haha i was just wondering what is the easiest enginge to sawp in there, i have a 87 b2000, i want to go with something with more poer ofcourse, i have heard of 302s and stuff, i was wondering about a turbo rotary out of an rx-7 would that be hard? anyways hit me back, Thanks