The Toyota "S" L4 DOHC engines are about the same at 93.5mm (3.819"), but IIRC the Ford has staggered bore centers like many older engines.
Your enthusiasm is commendable, but I'm afraid you're too far down the learning curve to understand exactly how much work this is. Just making the cams will cost several thousand.
93.5 / 25.4 = ~3.6811..., and this is for a chevy straight 6...
I can not seem to find much information on the 3.4L V-6. Would you happen to know its valve sizes?
I have finished hacking up the 4age head, and will be posting pictures of combustion chambers, intake/exhaust ports, water passage ways, etc in a few days.