Notice, the adapters at "Trans-Dapt" are only listed to bolt to carburetor type intakes.
The TBI to manifold adapters listed were Holley, they may have the same bolt pattern I dunno.
I took a quick look at my 5.7L Vortec, the diameter of the hole is near 3" or so.
I'm pretty sure I could make an adapter to put the TBI on it at home..
Only issue is, my "estimates" on labor regarding things of this nature are,,, errr WRONG Every time.
Still, I'm sure a handyman could fabricate one from steel or aluminum if the has a TIG setup in a few hours.
IF someone does this trick, I'd bet 10cents the hood clearance would come into play, time for the old "Mount the air cleaner on the fender-well trick"
Someone said e-bay had some but they were hand made..
Just Hang On a bit, this issue can be sorted out with hopefully a minimal cost to you.