So I got a lot of work done to my stock ls1, and half way through first dyno it lost like 40 hp and lost 10 to 20 psi oil pressure. Car still idles, starts and runs great but over 2200ish it sounds like a sewing machine. If u rev it quickly and tap the gas it sounds like someone is inside the motor tapping to get out. Lol. Car never ever had problem before. It has about 25 idle psi hot and 32ish cold. It doesn't go up much with rpm, and at cruise on highway it was showing a 2 to 4 psi change up and down.

Motor lost 30 rw from the first pull to how it is now.

I added 243s with prc eht valve springs and new 921 seals, ported ls6 tb, ls6 intake, ls7 lifters 7.4 inch comp pushrods, g5x2 cam, c5r timing set, new stock hgs, header gaskets, new plugs, ASP underdrive, etc.

My friend who is a bad *** builder who did all this at his new shop thinks it spun a rod bearing or has a loose wrist pin at the top of the rod. Could any of the knock or oil issues be related to the new parts? Oil pump failure? Or just too much stress on a wore out ls1?