I build all my own, and a bunch for customers. In fact had a hand (or two) in Tommyg29's Cuda's 440+6 (that is my old high school car). I've got several 451s in my background, plsu some 512s, 471s, and the standard 440s and 383s. Any non-factory stroke package will have it's own specialized issues to overcome. From poorly machined parts to physical interference to matching components that are all aftermarket and not as simple as "plug-and-play". What this means is you need a builder you can trust, and who you can relate to. Muscle Motors does great work, and sell a decent package if they don't build it. The last 496 I did had a rotating assembly from them. While not perfect (and I'm picky) it was very nice overall.
The engine is not the sum of it's parts, but the sum of the parts, the machining, and the assembly. So get them right and work with someone that you can talk to and more importantly challenges you with questions rather than just telling you what you need.
Avoid Hughes. Avoid Indy (yes- negative personal experience with parts and fixing customer's Indy crate engines). Avoid builders that put up fantastic numbers on the web. Like anything else - if it's too good to be true it probably is. Understand these engines have been under development for 50 years now and there's plenty of data points to compare to.
The old adage: Fast, Reliable, Cheap: pick any two because you can't have all three.
