So this past weekend, installed 228 Cam, new rockers, lifters, pushrods, ARP head bolts, 2600 stall converter, LT headers, ORY pipe, cutout on my 07.5 NBS Silverado with the 4.8.
Startup it ran without tune. Got the exhaust welded, drove it around the block to check up on fluids. Everything was good. Shut it off, started it up again, put it in gear, and now I'm hearing a ticking/knocking sound. Thought one of the converter bolts was loose, rechecked and torqued all them, popped off valve covers, all rockers were torqued fine, next step is to measure pushrod length. Any thoughts? Maybe lifter failure? (Highly Unlikely). Sooner the responses the faster I can get started. Thank you!

 

try getting a video of the sound. could be top or bottom end related. hard to tell based on reading this. have you checked all 8 for compression? did you prime the lifters? what kind of rockers did you use? could you have over tightened them and have held a valve open or ruined a lifter? not tightened enough causing a slapping sound and the pushrod moves up? the more info you can provide us the better we can help.