I have no idea what the sound is and I've been chasing it for a couple days so I figured I'd post a video and see if anybody else with more knowledge can identify it. It's not consistent enough to be valvetrain I don't think, but it's kind of a squeaking tick like the valvetrain would make. You can hear the normal valvetrain noise in the video and every once in a while the squeaky tic will pop up and it will make the sound it's making almost like a rattle just for a second or two or maybe three and it goes away again. It seems to almost make the noise In cadence with the engine shaking while the cam is loping. I tightened up the header flange where it bolts to the exhaust I've checked every single rocker arm for wiggle room or play. If I put my ear down by the wheel well on the passenger or driver side front I can hear it almost amplified a little bit, that's what led me to tighten the header flange which didn't eat a little bit a tightening but it didn't take the sound away.
It's a 70 C10, 350 Chevy with 400 trans and a fairly lopey cam, heads and rpm intake Edelbrock carb. The rockers and the pushrods are all brand-new maybe have two hours on them. All the valve lash was very meticulously adjusted. Let me know what you guys think
https://youtu.be/kBkpy7112FY