I have a question. You said you prepumped the lifters. Did you do this in a cup of oil. or when you had it together spinning the motor over while cranking?
these were manually pumped up with a pushrod in a cup of pure synthetic 10/40 . i used zinc rich break in oil and the assembly lube for the cam. and i have since changed the oil and filter.
i just replaced the lifters in a daily driven 318 using the same process , and they are very happy, doing great and street driven every day.
of course, the brand new lifters in the 360 that are crapping out are summit brand which came with the cam