The caddy motors are torque monsters. The specs that Wannabe quoted are for STOCK engines. I think that they are lower-RPM motors, stock redline of 5,200 RPM or so. You don't have to revv them up like a SBC, just gear them to take advantage of torque, and to keep the cruising revvs down. Similar to a 455 Pontiac.
When comparing the performance of two different motors, you have to look at the bore and stroke, not just the CID. A Chevy 427 has a higher powerband than a Caddy or Poncho, but at the expense of some low-end torque due to shorter stroke.
Rough rule of thumb:
Bore bigger than stroke: Oversquare- High RPM IE Chevy 350 4" bore, 3.48" stroke
Bore about equal to stroke: Square- midrange/high RPM
Poncho 428 4.12" bore, 4" stroke
Bore less than stroke: Undersquare- Low RPM Torque monster.
Poncho 455 4.151 bore, 4.21 stroke
