https://youtu.be/v2PrCewfMHE
Sounds kinda like a metallic clack/buzz, that only happens at ~1-3k RPM. It seems like the obvious culprit would be a noisy lifter, but I've bled my lifters many, many times and they all look to be in good condition. Noise becomes softer/quieter when warm.
Engine has been rebuilt with Wiseco pistons, Eagle rods, but I think it made this noise even before that. Subie 550cc injectors, Jim Wolf S3 cams, S15 turbo.
This doesn't sound like bottom-end noise, right? Could it be I need to re-shim the valves?