I dont think you can refer to a 427 and a 460 base motor as big blocks in the same context,they are not simular in any way,an fe motor looks more correct,sounds better and has tons of torque and bragging rights,with alloy heads the wieght problem is a myth,Carrol Shelby was no fool,,50/50 is 50/50.Small blocks rock too,and have character all their own,I would definately prefer the small block over a 460 series,mostly because of weight,and a 460 isnt correct looking in any cobra.
427 isnt the only consideration here though,it is hard to buid a 427 under 500 hp with decent parts,and 361's,390's etc can be built cheaper,lots of torque and power,,and they look and sound right.
I suggest reading "insights into the fe engine by Jim Dove,
http://www.doveperformanceparts.com/...insightfe,most peopel who dont love fe motors have never had one,or dont understand how different they are,Tk