I don’t really think it’s the exhaust but I’m going to check it closely before moving forward on the valve train..
CHEAP easy way to look for exhaust leaks... Low Effort Required - Much easier than all the other stuff you have done!
Get yourself a spray bottle. Ladies hairspray, 409, Whatever.
Get the water good and hot and fill the bottle 3/4 or so full.
Get some good soap. Dawn or something like it.
Give the bottle a good healthy squirt. Don't shake it up, just swirl it around in the bottle.
Then, with your bottle of soapy water in hand, open the hood, and go crank up the truck.
Immediately walk around to that side where you think the ticking is coming from.
Spray it. Don't be bashful, give it a nice coat of water and soap.
It you get bubbles, you have the leak we have been talking about. If not, well it was a cheap way to hunt for it. WHATEVER you do, don't let the motor get scalding hot. It will just dry out the water and you loose the effectiveness.
MOST IMPORTANT: If you snatch your lady friend's hairspray bottle and dump it out for this project - Your death isn't my responsibility. You have been warned!
I think the noise I’m hearing on the right side pipe is just the valve noise being amplified down the line. On the header/manifold area I hear just a light whistling clicking sound like I do when I listen directly on the injectors, then after the 3 bolt flange I can hear the knock for about 2 feet on the pipe before it’s not really perceivable anymore. I’m down there touching the stethoscope to everything and it’s driving me crazy lol.
By far the loudest places I hear the knocking sound with the stethoscope is on the fuel lines right where they bolt to the brackets on top of the valve covers. I’ve cracked them and all that changes is the motor bogs down but the knocking is still there in the background until it comes back full force once injector is tightened again.