I think there once was a time when a "conservative democrat" existed but you have to go way back to the era of Strom Thurmond and James Eastland.
It was roughly 1968 when genuine American patriots (pro-God, pro-life and pro-military) abandoned the Democrat party in droves. By the mid to late 80's (when Perry endorsed Gore), that party was into full-tilt Marxism (with the likes of the vile Jesse Jackson among the candidates).
Also, the reason why Tip O'Neil turned hostile on Reagan is that Tip got mad that Reagan reached into to his caucus to build his coalition.