I know you can do a vertical radiator setup with a griffin and the like, but is it possible to do it with a stock radiator? Just wondering because it would be nice to have the extra room.

 

Well, nothings impossible.

Here're your options:
1) shorter radiator (go with more cores/thicker, or brass to make up for lost heat capacity).

2) chop the lower radiator support, drop it 6" and drag it on the ground.

3) remove the upper radiator cover. Chop the front cross-support and raise it 6". Redesign the front hood, lights, 1/4 panels.

There's only about 1" of rubber gasket below the stock radiator, not much to shave back. The stock rad is slanted a fair bit as well... though it "should" be possible to make it a "bit" more upright if you get slimmer fans, avoid an electric water pump, and are willing to chop and weld the lower rad groove closer to the engine.

Without changing the rad dimensions you're just wasting your time. If you need more cooling, get an all-Aluminum dual-core rad. Griffin's and BeCool's are ridiculously priced. I picked up a 2" dual core off ebay for ~$150. Stock fittings and everything. Expect to trim small flanges and such to fit your engine bay with any non-stock rad.

(If you go with a thicker rad core you'll probably have to trim the fan shroud to clear an electric-pump housing... if you have one).