Engine Swap

what are the differences between the 92(i think)-94 DOHC engines as compared to the 89-94 SOHC engines? are the electrical connections different? would it be just a drop-in-and-connect swap with harnesses for that engine or would i just be able to use the original harnesses?? im just curious...i wouldn't be doin it any time soon since i dont have the funds, but maybe sometime over the summer or something...