Earlier in the 1700's Barbados put forward a bill that would only allow a set ratio of blacks:whites on the colony, as many feared if the black population became overwhelming they'd revolt against the white, colonial rule. The bill failed however, though it attracted some interest in colonies such as South Carolina - a colony very much culturally linked to Barbados - and more importantly other British Caribbean colonies.
Let's say this bill passed, and so in other colonies like Jamaica the same sort of bill passed. This means that the black-to-white population ratio is much reduced and would probably be more like the Southern Colonies on the mainland where whites outnumbered blacks - though the tropical climates of the Caribbean would probably still mean blacks outnumber whites.
Anyway let's say this causes minimal butterflies and the Stamp Act is passed as IOTL, the Stamp Act actually hurt the Caribbean colonies far more than the mainland ones. The main reason for their neutrality was a worry that, in the chaos ensuing a revolt against the British, the slaves would rise up and overthrow their masters. ITTL that fear would be dulled and so we might see those colonies join in with the mainland ones. While the Royal Navy would be a major factor to overcome, the Franco-Spanish navies could keep the British occupied enough and so we might see the Caribbean become an 'American Pond'.