4.6 cobra ina 67FB?

Hi, I keep haveing this recurring dream/nightmare! It goes like this... In my garage ther sits a 67 mustang fastback up on stands, the engine and 4-speed are under the work bench with R.I.P. painted on there sides, the 9" is still under the car...Hmmm what to put back under the hood? A 302? or a 351? or a 331 stroker? or something completely different? As I am pondering this delemma, the phone rings, It is my Son in Law telling me that the Insurance Co. is going to sell that 01 Cobra that was totaled at his Towing Co. In all the Car Shows I have been to I have not seen one 4.6 in a classic Mustang.. The dream ends with something WICKED growling under my 67 fastback... Are ther any articles about tranplanting a 4.6 into a classic stang out there? For starters, Will the heads even fit next to the shock towers, Thats just one, I can think of other problems also the length of the tranny etc.. Any input at all will help me sleep better!!! Thanks, Floorhoar