Hey Walt... the core support is only loosely bolted in. Its tilting back at the top about an inch or so, Id guess.
I hate to hang sheet metal while still playing with brakes. So its leaning back at the top far enough for the shroud bolt to hit the fan tips. That could net me an inch clearance on the top. The best route for me to go is to "S" can the down flow stuff. Thats soo Flathead V8-ish LOL. Theres almost 27-3/8" (+ or -) between the the CS uprights. A member here is getting and upper crossflow mount to me. I figured I can trim some off the front, re-drill the three holes and move it forward so theres about 1/2" between the rad and the CS. I believe the later lower mounts bolt into the core support lower frame as well. Maybe some notching down there to move them forwards as well. Ideally I'd like to see about 2 inches between the fan and the fins. Make sense?
Luckily, this is a GM project and not some weird dodge or ford where everything fitting is "iffy" at best. I love the input ... please keep it coming. If the front clip were back on, Id have some constants to work with, but for now, Im still measuring "Air". Bill