If the Founders were "conservatives", how would you categorize those who chose to remain loyal subjects of the Crown?
It was the imperialists in the mother country who were radically changing the status quo, imposing central Parliamentary control over a bunch of colonies which had been left to pretty much govern themselves. The American "Revolutionaries" wanted to preserve "English liberties" against an encroaching remote central government. That puts them right in the same camp with today's conservatives. The American Tories were analogues to today's liberals: happy with expanding central government. There's a lot of historical literature documenting that the American "revolution" was a conservative one, a movement to protect gains in freedom which had already been achieved. Just read the Declaration of Independence. It accuses the King of many radical moves against existing rights and liberties.