Okay. shop built motor and installed it but did not break the cam in ?sounds shady!
Your last post said untill u rolled to the side of the road ?This is not how u broke the cam in ,driving?not good.
Loud noise from valve cover ,warrants pronto shut down of motor and inspection.
Driving the car right after break in ,U were driving under 55mph and varying the speed and rpms ?
Lastly u shurely wouldnt stomp the throttle on a new motor with the engine still cold ,with the break in oil and filter not being changed?
No 1 drain oil into a container and send it to a engine oil analysis lab to determine exactly whats in the oil,just bearings or blasting media,No 2 sounds like u need to let the engine builder have the car and let the auto shop build install and break in ,also test drive the new engine and call u when complete so u can go get it and drive away happy.or like U said build it yourself and have no confusion over where the mistake was made.or!! u just mIGHT HAVE MURPHYS LAW GOIN?good luck.