[blykins]

No issues with overheating as long as you have a good water pump and radiator. I have lots of 400-500 ci engines running around and they all run as cool as cucumbers with the right components to support the engine.

As with all new rotating assembles, I would recommend that the block be machined to make sure you start off with a good solid foundation. This includes boring/honing to fit the pistons, align honing the mains, square decking the block, etc. All of this adds to the quality and detail of the build.

A lot of the 427 builds use an aftermarket block so that you can use a 4.125" bore and a 4.000" stroke. In that case, there should be no clearancing needed (although you always check). You can also get around 427 ci with a factory block and a 4.125-4.250" crankshaft. In this case, you will need to mock up the rotating assembly, see if the rods touch anywhere, and then clearance as needed.