[Excaliber]

While it may be stronger I've seen pictures right here on Club Cobra of a Shelby block with a hole in the side! Everything is a trade off when it comes to building an engine or a car. Expense vs application vs risk, etc. As noted above a standard issue FE block (390-428) built within reasonable limits is a good cost alternative. With a hydraulic roller cam (an expensive option) you can get good horse power at or below the 6000 rpm range and maintain excellent reliability.

I would certainly prefer a 427, and a side oiler block at that, myself. Setup correctly there is no reason to fear 7000 rpm with a side oiler, they were built to take it. Now if you choose to run it at a lofty 7000 rpm your going to increase your risk of failure of SOME component no matter block what you run. The risk also goes up when you stroke it. The SHORT STROKE side oiler with a steel crank is still an excellent choice today.