Rebuilding costs all come down to the shop and the work needed. It could be $1000, it could be $5000. Get some quotes from some reputable places and look around for 390's. If it were my car and I had the money lying around I'd get the 390 and put it in and leave the 352 as a project motor.
Where in this country are you located ? Just a skip and jump from the Talladega NASCAR track is a quiet little town in Alabama named Oxford. To me Oxford's claim to fame is it's the home of a priemere FE Engine builder named Mike Osburn. Mike has quite a list of builds including restoring some prize winning Thunderbolts that run much faster than they did when they were new. If it has anything to do with the FE series engine Mike knows about it. He currently races a 64 Galaxie quite succesfully along with building nice stuff for folks he knows. The largest part of Mike's work comes from friend's references as he doesn't bother with advertising. The biggest thing is his fee is very reasonable for the top quality work he turns out. If you want the real skinny on what your 352 Interceptor can be with a little effort and cash give him a call. ( 256-831-4779 ) He is in and out, very busy man, if he doesn't answer wait a bit and call again. I don't give his number out often but you have a diamond in the rough that needs a bit of polish. Tell him Honnel's boy Petey refered you thru the Ranchero site. Mike built this one for me an' it runs even better than it looks.
Based on what he said was wrong in his OP, IMO it will be on the $5 grand end if he has the work done for him with quality parts. Swap time.