What features of cephalopods have allowed some species to grow to large sizes relative to gastropods

marine bio :)

The biggie is the closed circulatory system. This feature allows an animal to be "thick" while still supplying oxygen-bearing blood to all the body cells.

Another thing is the squid giant axons. These allow good rapid coordination of muscles at a distance from the brain. (Other large organisms have myelinated axons).

Most gastropods have a heavy shell and do not move swiftly. That's a recipe for not being able to cover a lot of ground while getting food. Squid swim, and have the potential for finding more food.

Last, consider the eyes and oversized brain. These are part of what make a squid a successful predator.