Why Build a Caddy?
Lets start with the advantages of using the 472/500 engine family as a basis for your next engine. This engine family has earned a reputation for longevity and power, partly due to the high initial build quality. You are starting with an engine with tighter specs than many new 'high end' cars, to include the square-ness and uniformity (lack of casting shift) usually expected only in high dollar full race engines, from the bore centers, to the deck surface, to the rotating parts centerlines, to the exceedingly high nickel content of the castings (like a 'Bow Tie'™ block that costs more bare than your complete core engine).
These engines are also very light for their size, being within 60 Lbs of a small block Chevy, while still being tougher and more wear resistant, due to the high quality materials and castings. They have numerous other advantages, including easy access to the distributor and oil pump, dry (no coolant passages) intake, individual ports (not siamesed to lower production costs while hurting flow), conveniently angled spark plugs (easy access in the tightest of installations), and they are all internally balanced, eliminating the need (and inefficiency) of external balancing.
Another prime advantage, is that due to the stock 11 degree valve angle, and well designed chambers and ports, it is not unreasonable to expect in excess of 700 real HP out of a normally aspirated engine, with common ported production heads - no exotic machine work or aftermarket castings required. For the milder builds, this means that you are well within the range of easily attainable power, without stratching the limits of the stock block and heads.
The Cadillac advantage really shows, when they are pushed towards the limits. The fastest gasoline car on the planet (and the ONLY gasoline car to exceed 400 MPH, at 415 MPH), was powered by a Cadillac 472. Stock 2-bolt block (.060" over), stock (cast) crank, and our off-the-shelf Pro/Comp ported stock heads. Nothing exotic - not even a roller cam. The Cadillac engine is not only the fastest gasoline car, it is the fastest (by a wide margin) single engine car using production hard parts. What is the limit of the stock 2-bolt main block and cast crank? We haven't found it yet, at over 2000 HP.