I've got a question for those who know about the blocks used in the modular family. I must admit that I'm not too knowledgeable technically speaking when it comes to engines so please give me some slack. First of all a 5.4L should have a bigger block than a 4.6L right? A bigger crank needs a bigger home to spin in???? But if this is true how can you buy stroker kits for existing engines, surely part of these kits is not a replacement block?!!!? So then are the alloy blocks from a 4.6L Mustang Cobra interchangeable with the iron blocks from a 5.4L Boss. Surely that can't be possible but it's a burning question for me!!!! Just how much weight can be saved with an alloy block in a 5.4 L engine, does anyone know? I believe that with the two cars being so close now in terms of size that this must the main area where Commodores are picking up their weight advantage over Falcons. And what, besides from cost, are the disadvantages of using an alloy block??? I've heard iron is stronger &, more importantly, consistently stronger, and also quieter than alloy in terms of unwanted engine noise. Maybe, BUT IT'S ALSO A SH*^-LOAD HEAVIER!!!!! Could someone who knows fill me in!!! Why in the hell are Falcons giving so much lost performance away for the sake of an iron block.