engine ID and specs

I'm looking at a 1999 50 foot Bluewater with Multi port 502's rated at 400 hp . How do I tell the difference between a gen vi - v and iv engine ? Do the engines used by the builder always reflect the same year as the boat ? I looked at a 1998 of the same make and it had throttle body injection . Was that the cutoff year for the throttle body ? It's hard to find specs on these engines (ie , 4 bolt mains - steel crank and rods - roller hydraulic cam - etc . Any more info + or - would be appreciated .

http://www.ehow.com/list_7356459_chevy-454-specifications.html

THis will help a bit. Externally, the easiest to spot differences are the provisions for a mechanical fuel pump (or not), the serpentine belt, and the vortec heads. The Gen V is by far the least desirable, btw.

so -- a standard V-belt Crusader would be a Gen V engine ? What is the undesirable thing about this engine ? Is it a thinwall casting or something worse ? Is the Vortec 8100 a better choice ? the numbers get confusing when it comes to the marine world - just lookig ahead to the future when it comes repower time .

The "engine year" and the "hull year" frequently do NOT match but that isn't a cause for concern.

The Gen V is the least desirable because of its 'bastard' status.

Throttle bodies died around the timeframe you suggested - easiest to pin them to a serial number vs a 'year'. they are also undesirable because they have little support because they weren't around long.

The specs are easy to find, you just have to invest in a factory service manual. For the most part, for a given vintage, the short block product was produced by GM and then shipped to the Marinizing OEM who would complete the engine; ie the internals on a standard production engine are common across brands.