“Historical it was a fact they changed it to pursuit of happiness from security of property.”
And your evidence for this “fact” is what, exactly?
John Locke used “life, health, liberty and possessions” in his 1690 book. Locke also used the phrase “pursuit of happiness”. But there’s no evidence that Jefferson was citing Locke.
Jefferson was certainly influenced by the Virginia Declaration of Rights that he helped pass one month before he wrote the Declaration of Independence. His fellow Virginian George Mason wrote
“That all men are by nature equally free and independent, and have certain inherent rights, of which, when they enter into a state of society, they cannot, by any compact, deprive or divest their posterity; namely, the enjoyment of life and liberty, with the means of acquiring and possessing property, and pursuing and obtaining happiness and safety.”
Jefferson used the Virginia Declaration as a basis for writing the Declaration of Independence.
“For the reason I gave that slaves were property and that would of given the south the constitutional right to slavery.”
You confuse the Declaration of Independence with the Constitution. The Declaration contains the “life, liberty, pursuit of happiness” wording and it’s an announcement of American secession from Britain, not a document for setting up the American government.