Does edelbrock still make a webber and four barrel manifold for these. i bet they got one in stock somewhere. i would give em a call. I was thinking there were parts out there for s8 fords.
biggest problem you got is young guys dont do straight 8 stuff and old dudes dont like to sell stuff on the net. Best to hit the swap meets and ask every person that will talk to you if they have herd of anyone with the parts you need. they were made by a bunch of people at one time. I am sure some old rodder has what you need in his garage in good shape and ready to go.
I would not boost a 100 year of engine. or 80 90 whatever. Unless you have just rebuilt it i would leave that option on the table. Putting the stright 8 in storage and going 350 would be safer. You could always go back to oem spec.
Boost will have oil pooring out of that motor. Not to mention putting load on everything. If you do boost it you got to build it up to take the turbo. gaskets and valve seals were never made to take that kind of abuse they will be spewing oil. i was thinking the crankcase does not have good venting on those old 8s as well. But i have never built one. 350 is to cheap and no one cries when it goes up in smoke. junk yard short block and fab up some custom mounts so you dont have to cut into your chassis would be trick. i think they fit if you lower the front of the car and mount the engine back at an angle.
hope that is not unwanted advise.