A 347 stroker engine with alloy heads is a hell of a lot of fun. Huge bang for the buck.
If it's going to cost a bomb to build one though, I'd look seriously at just buying a 5.0 litre roller rocker with alloy heads, they really sing and will give you as much fun as you'd want to have while still being workable and durable.
Eagle Engines may be worth checking out, I have heard and read some good reports.
