I was just looking around on youtube and came across these 2 videos.
http://www.youtube.com/watch?v=ppPZsI7Xy30
http://www.youtube.com/watch?v=APCl012FXhs&NR=1

It shows a guy putting a 292 crank in a 250 and it clears just fine. The only problem is that the connecting rods were too long and it pushed the piston out the top of the block. Couldn't you use a 292 crank in a 250 as long as you got short connecting rods? Would there be an advantages/disadvantages?

69 Buick Special Deluxe. Intercooled Turbo Chevy 250 @ 15psi on a stock long block. It's kinda fast.