Blueprinting means they took extra care putting the engine together. It can get very expensive and time consuming. Essentially the engine is as perfect as possible: production variations are machined out, balancing/assembly is super close tolerance and the best of everything is used.
Genuine "blueprinting" comes down to: Spending countless hours polishing, machining, using extremely sensitive (and incredibly expensive) measuring equipment and testing everything. I would estimate that you would probably spend more money on the labor than for all of the parts purchased new.
So if you worked for Boeing, you have a good chance of a genuine "blueprint". My buddy who assembles main engine pumps (that can empty an average pool in 6 seconds) and has a huge amount of test and assembly equipment can probably pull it off to degree that should be measureable on a dyno. But they have some 50+ ME's that spend weeks on a single pump that has only a few dozen moving parts....everything is microscoped, weighed, polished, photographed, bench-tested, assembled and pre-production tested.
At your basic speed shop it means they didn't take any short cuts.
Or better yet: Blueprinting can mean just about anything, as long as proper care and parts are used.
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I think the NSX-R had different intake, exhaust and other goodies to make up the HP over normal stock.
I'm not sure how much extra care can one put into an NSX engine? It is at pretty tight process already...
Drew