I guess one relatively simple way to try out your theory would be to remove the fan assembly and go for a drive! If they're really getting in the way (both off and on), it should be fine at any speed above 15 mph or so.
....and I
was going to suggest that but don't want to be responsible for blowing up your hopped-up Big Block.
I will add this: I don't run a fan at all on my '84 318, my '98 318 QC 4x4, or my '01 RC 318 4x4. All Freeway here; if I run into traffic they are all still cool unless there is strong tailwind, I get into gridlock or say 3 red lights in a row at 80 plus degrees. My '01 QC 360 4x4 has a small electric fan (because I care about it, lol) of unknown origin (thought to be from an Omni) with a 15 amp switch (it runs real slow, lol) and I barely ever use it.
I suggest a little plan for your highway experiment: have a quick-connect pigtail for your fans and make provisions to use zip-ties to mount it and plug it in real quick if you run temperature. I doubt you will need it, but, be prepared in case you have other issues.
Otherwise, yeah, I'd butcher that Ford setup in half and go hit the road.
