Lifter knock after rebuild

Ok, so for those of you who have read some of my previous post are gonna realize I don’t get things done too fast. We just had out 1st kid and wife will only let me in garage every once in a while.

I rebuilt the 289 w/ all new parts except the block, crank and rods. I installed a new cam and lifters (summit generic of Edelbrock performer plus). I just recently got the engine timing set where I like it and the carb semi tuned. I have only ran this engine for about 2-3 hours and I have changed the oil once so far. I do not have tags / insurance on the car yet so no real driving, just 1 trip around the block and lots of running in the garage. I did a proper break in and followed the cam instructions.

I have noticed I have a lifter knock at idle that increases with RPM. I started investigating and pulled the valve covers. I thought it was coming from the left bank so I started w/ cylinder #1 and pulled the rockers / pushrods, ran it at idle no change, reinstalled. Then on to #2, pulled the rockers / pushrods, ran it at idle and knock when away. I reinstalled rockers / pushrods and knock came back and then repeated the process one more time till I was satisfied this was the cylinder.

So questions.......

I have no real time or miles on this engine, so do I run it 10,000 miles w/ regular 3K oil changes and see if it goes away or fix it now?

Will it cause any harm if I let it go a little while? I would like to focus my attention on the front suspension alignment and drive the car a little (also rebuilt front suspension when engine was out).

If I fix now do I change all the lifters or just the ones in question? I have an extra set from my engine rebuild kit. Camshaft came with a set and so did the engine kit. I used the lifers from the cam during rebuild.

Thoughts? Thanks and advance!

I did measure the pushrods and lifter preload and per my limited knowledge both are correct. I broke the cam/engine in exactly as the cam instructions stated.

I have eliminated the #2 cylinder as a possibility, the noise is still there with the 2# pushrods removed. I didn't let it warm enough during testing.

I have inspected my oil closely after changing and no signs of metal shavings unless they are all in the oil filter? So I doubt I have a rounded cam lobe but I will investigate.

I will see if I can upload a video w/ sound. I'm gonna adjust the timing a little to see if it is possible detonation sound I am hearing. I am running 87 octane. Not sure where my compression ratio is?

If I change all lifters should I break the cam in again following the instructions?

It very likely could be a header gasket as they are missed matched.

I purchased a mechanics stethescope yesterday and the noise seems to be not coming from the lifters, any one cylinder, valve train, rod bearings or mains.

The tick gets most intense at the timing cover and weaker at the water pump. I installed a new timing cover, timing chain / gears and water pump and re-used the fuel pump? I'm gonna buy matching quality header gaskets, install, run it till warm and then pull the fuel pump and see what happens. I will keep you posted.

No video so far my wife has the Iphone and my hobbies just piss her off....

Thanks for all your feedback!