Are you sure the cam was on the base circle intake/exhaust for each cylinder you adjusted?
really easy way I have been setting valve lash on pedestal style hydraulic rockers for 40+ years.
with the valve covers off. tighten all of the rockers to 0 lash- when you cannot move the pushrod up and down and a slight drag when rotated
rotate the crank with a socket 45 degrees and tighten up all the rockers again to 0 lash
Repeat the process for 2 full rotations of the crank
Once you are done then turn each rocker arm an extra 1/2 to 3/4 of a turn depending on the cam. I start with 1/2 turn,
That's it. You're done. No finding of TDC or getting the cam on base cirlce for each valve.
with the valve covers off. tighten all of the rockers to 0 lash- when you cannot move the pushrod up and down and a slight drag when rotated
rotate the crank with a socket 45 degrees and tighten up all the rockers again to 0 lash
Repeat the process for 2 full rotations of the crank
Once you are done then turn each rocker arm an extra 1/2 to 3/4 of a turn depending on the cam. I start with 1/2 turn,
That's it. You're done. No finding of TDC or getting the cam on base cirlce for each valve.
Sounds like you are adjusted too tight...especially with popping in the exhaust. If I hear slight noise I'll pull the valve covers, reinstall the upper intake, and run the engine listening at each valve for the culprit. ( can be messy ) I've seen stubborn and bad lifters right out of the box. You want the lifters to bleed down before adjustment. You should be able to push down on the pushrod and feel the spring in the lifter. Dont push it down fast and dont do it multiple times- pumping them can cause adjustment issues and youll need to wait for them to bleed dowm again. Sometimes people get confused with setting zero lash because they think that means all the way until they can't push down on the lifter plunger. The result is overtightened valves. The lifters need to sit and bleed down before adjustments can be made. Stud mount rockers can be a PITA. Stud mounted rockers can be adjusted with the engine running by feel and sound.
I kind of think that is the best way but it's way too messy for me. Back in the day I cut the center out of a valve cover to try to stop the mess of oil going everywhere but it was still messy.
If it were me, I would run it a little while to see. If it get louder, stop. I have heard many stories of lifters being junk but haven't run into it. There is no chance it is a header leak? The valve guide were done or checked when the engine was rebuilt?
So the valve train on the 331 in my Coupe is noisy and I replaced the Comp Cams lifters with Ford Racing and it didn’t change. Had to swap to Scorpion rockers due to the Crane Energizer rockers not having enough clearance for the cam lift and still noisy. Geometry is spot on so I have just chalked it up to valve noise. Talked to a couple of engine builders and they both said it’s nothing to worry about. It has been this way for years.