You can change it anytime now, it's all really a matter of opinion anyways what is best. The important part is you dumped the old oil and have some new oil in to flush the system. Was your engine pretty sludged/varnished?

 

Ya the under the vally pan it was light brown and some of my valves took some real cleaning but she is clean now I know if I paid someone to do the the head gaskets they would of just put that all back together and never cleaned it, so I am glade I did it my self!!

 

Yeah mine too before you change the oil you may want to put in a quart of marvel mystery oil (~$5) and drive for another couple hundred miles just to do some more cleaning of the bottom of the engine that you could not get to.