[eschaider]

The engine as we use it is a flyweight. The only way I can figure the 600/650# numbers must be with clutch, flywheel, accessories like AC and probably the shipping crate for a complete assembly.

Easiest way to check the weight is a tear down and a scale. You'll be positively amazed! If you supercharge it use a Teksid aluminum block (2001 or earlier production) for the thicker casting. You'll pay a small weight penalty but it is reliable at 600 HP. The '03 and later blocks use a thin wall casting and much improved (at least visually) main webbing and caps. The cyclinders don't have as much aluminum supporting them and power levels above 600 HP (superchargers?) will literally push the block apart. The thin wall castings have a particularly robust appearance to the outside of the block, but the real giveaway is they only weigh 80#. The block you want will weigh 105/110# in aluminum. I think the '02 blocks are the same as the 03 and later but I don't know for sure.

By the way Sean Hyland is probably the Keith Black of modular engines. The guy has done a incredible job of producing high quality, aftermarket parts for the engine that simply can't be found anywhere else. Important things like single groove stainless valves are only available from him. He makes an aftermarket all aluminum block for both the 4.6 and 5.4 that is stunning. Cyclinder wall thickness with the large 3.7" bore is equal or greater than the old 3.55 bore Teksid blocks.

Ed