I thought I would put my experience with Dyno-flo in here. I had a 582 built in 2005. We drove to the shop and witnessed the dyno. The engine came up a bit short on power. (911 instead of the expected 950) I was happy with the customer service and the fact that Scott kept the manifold for porting and was helpful.
After installation in the car, several months after picking up the engine due to a bad paint experience on the car, I had a water in oil problem. We pulled the engine, returned it to Scott, who promtly pulled the engine apart and found that it had an intake gasket fail at the water jacket. I put the intake on after he ported it post dyno. He freshened it with bearings, checked it all out, and only charged me $250 for the parts and labor.
I call that pretty stand up. Considering I put the manifold on, the water issue was my fault.
I have no idea what happened to the 454 small block in question, but I did want to add my good experience for a balanced story.