Could mollusks become extremely large?

In a brand baby spanking new world I am building, appropriately named Escargard, punningly named by the AndyD273, mollusks have become the dominant form of life. Resulting in aliens similar to those below

But sadly the longer I thought of such a scenario, the less likely It became, while many mollusks lack the scaling problem that insects face, they have their own. The gelatinous structure of the body of mollusks makes it difficult to rightly scale them.

Without editing their biology, what is the largest I can make a mollusk? What changes can I make to mollusk biology to allow them to become massive?

posted over 7 years ago

Uncle Tres‭

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