what budget do you have ?
any good junkyards, er, i mean, "recycle" places you can browse for what you will need for parts ?
how good are your fabrication skills when you can't find what you need ?
how good are your electrical skills ? this is especially important if you choose to go modern power plant with computer controlled devices you need to integrate with a simple older wiring system.
just a few things i thought of. not trying to say you don't have the skills to do a swap of your choice, just some things that have bit my old bony azz in the past.