I've been running Valvoline VR1 in the old cars. Also add half bottle of GM's EOS with each oil change. For breakin besides the VR1 use The Comp, Crane or Lucas additive s shown above or a full bottle of EOS. There are a few others as well. Valve spring pressures can also be a factor during breakin. If I'm running dual springs w/ an inner damper I remove the inner spring and just use the outer spring and inner damper spring till after breakin and sometimes some easy miles 50-100 before installing the inner springs. Anal?? Maybe but with things today you need to be careful. Also be sure your lifters (non roller) are spinning in there bores when using solid or hyd lifters. If a lifter is stuck and does not spin it'll wear the cam lobe AND lifter right down. Could have been something like a burr that was not removed or funky bore itself. Yep even on crate engines you need to check things over well. Sorry to hear of your problems....