As some of you know, I have a 95 mark viii motor and trans in my 67 f100. I've seen threads about converting an entire car from obd1 to 2, and it being a nightmare. How hard would it be to convert just the engine?
I've never done one, it's a lot of work and parts. I would never do it for looks alone. The coil on plugs get expensive and I've had to replace a few. I've never replaced a regular coil on my older gen 1 Mark VIII's yet.
Probably more than you realize, especially with the automatic transmission?
The best advice I can give is to get an EVTM for both and compare pinouts and see if you're up to the challenge.
The coil on plug conversion, while certainly doable, is only part of the challenge. Then you have fuel injectors, cam/crank sensors, ACT/ECT sensors, MAF sensor, O2 sensors, TPS, IACV... just off the top of my head, without consideration of the transmission control.