[JoeC]

There seems to be a lot of confusion about the engines here. The way I see it, there is no modern big block like the old engines. In the 60s and 70s there were two different size blocks that became known as Big block and Small block Chevy engines. You don't have 2 block sizes today. The ZL1 (RPO) and the CanAm (race engine) were two different aluminum big blocks. Road racing Corvettes and Super Stock drag cars used the ZL1 block because the CanAm block was not legal. Top CanAm race cars and Pro Stock used the stronger CanAm race block. The CR5 is a race version of the LS1/LS6 RPO Corvette engine. It is more like a small block but since there is no modern big block there is no need to refer to it as a small block. The 427 CR5 is a great engine but it is not a modern day ZL1 or CanAm big block engine. In my opinion it is a completely different animal.