tercelrcr

Hey guys so here is the deal. I have a 95 civic with a swap it has a d15b7 bottom end with a d16z6 head have been told its a mini me wlswap. Had it rebuilt about 7k ago and just did my seccond oil change on it. I do them every 3500 or so as I have alwas done and was taught to do. I run 5w30 synthetic blend in it as recomended by the honda mechanic who rebuilt the motor. When I went to the oart store they were out of regular synthetic blend and the parts person insisted that high milage synthetic blend was the same. After the oil change now there is not a slight like knocking noise from the motor. It almost sounds like there is somerhing loose but I can not seem to find anything. As soon as I give it a little gas the noise goes away. Is there possibly any corilation between the noise and using the high milage oil? Or is the noise something I should be worried about?