engine rattling

[slowpoke]

app 200 thousand miles on long block rebuild 2 years ago . built in mexico its an LB8 motor had uni reprogram for lessor power to drop boost below 40psi was hitting 43 on old engine oil always done around 10,000 miles changed rocker shafts on intake side in summer cause jakes where rocking at idle, then did top set about month latter and thought valves where sinking into head because clearance on jakes from detent where low turned out was my mistake switching from feeler gauges ( set them to .251 instead of .276 . could an injector make a rattle noise? the higher the rpm the louder the noise.