535 supercharged first time start up?

I just went through a lifter scare with my fresh Ford 400 build. I spent a lot of money on Crower Cam Saver lifters and built the engine with those. On startup, everything seemed to go well, but I could hear some light valve train noise. Since I was in the middle of break in, I didn't cut it off, but went ahead with the break in.

As far as cam lobe and lifter face wear, it went well. The lifters though were noisy when the engine got up to temp. I tried different preload settings, to no avail. So I searched around for another set of lifters. I ended up going with the cheapest Melling lifter ($4.99 ea.) from Summit. I installed them and held my breath and started it back up for another break in. Amazingly, I was successful and now the engine has probably close to 1500 miles on it and is quiet as can be cold or hot.

All I can figure is, somehow, the valving in the Crower lifters was defective. Sometimes the newest and shiniest thing ain't the best.