ProMod80

Hey guys, Im new to this forum and i am seeking some answers so if anyone could help me out that would be great! I picked up a rear mounted turbo LT1 car a few months ago that had some issues and i have been trying to get them fixed. The turbo kit is a home made deal based off the STS kit. When i got the car it was blowing oil out of the turbo. I found a check valve in the return line(i don't know why he had one there) so i removed it and that stopped the oil issue at idle. When you drive the car or get on it it will blow oil back out of the turbo and smoke. The feed line has a pressure regulator that is adjustable. I am wondering if the pressure is maybe too high and that is what is causeing the oil blow by. I just don't understand why it will not blow any oil while idleing but it blows oil and smoke while driving. Any help that anyone can give me would be great. Also it has a Holset HX 40 turbo if that helps any.