Given everything that's been replaced....... I don't know what to tell you. It sure sounds like valve train noise, and since the disable cylinders test didn't change anything...... valvetrain is pretty much the only other thing that makes those kinds of noises. It's *possible* that it has always been valvetrain noise, just the CAUSE he changed with the parts changing..... Was it quiet before the first rebuild??

 

From what I remember, when I first got it running I did not hear any ticking or anything. I'm pretty sure I first heard it when I swapped the EFI out for a carb, but I don't think its related... its possible it was there sooner and I just didn't notice. What are the chances that out of the box lifters from a reliable source would be bad? Because if it is valvetrain related, then most likely it would be a lifter that's not pumping up, which after 3 different levels of preload, would seem like it would be a lifter issue. But a brand new lifter?

 

Just because it's new, doesn't mean it's good..... Part quality has tanked dramatically in the last several years. Everyone moving production to China, or some other third world country, that use lower quality materials, and have no idea what "QA" is..... Not sure if there is a way to test lifters while installed..... But, two different sets having a bad one, or two? Not sure what the odds on that are..... Though, I went thru three store brand autozone distributor caps on my firebird, before I finally broke down and bought a better quality Accel cap.... Getting stranded with a no-start within HOURS or installing a brand new part got old right quick.

 

Gotta love the world of automotive I grew up into lol. Right as I get to the age where I can buy and work on my own vehicles, its almost impossible both literally and economically to find parts that aren't chinese garbage. I already bought a new set of manifold gaskets, and I'm going to throw on the old manifolds just for the hell of it. That way I can confirm its not a header crack/leak before I pull the manifold and muck with all of the lifters. That would save me the expense of buying a new intake manifold gasket, coolant, and oil lol. Fingers crossed its just a really weird exhaust leak, but at this point you never know. I'm sure hughes will back their product if it does end up being a bad lifter, just would be annoying because I'm sure I would have to send them back before they send me a new set, which creates a whole pain in the *** problem of one not having the truck to drive for an unknown period of time, but also having it sitting with the intake off and possible condensation making its way into the crankcase.

 

Buy a good set of dead soft aluminum, or copper gaskets.. They simply do not leak..... and may even be re-usable.

 

I have a set of remflex gaskets on the headers currently, and the sound didn’t change lol. The only other thing I can think of is that the Hughes 5007 lifters are listed as a fast bleed down, but I feel like the noise I’m hearing is not an issue with bleed down speed if it is lifter related

 

To me, the sound seems metallic and on top. I wonder if you were to put pressure on each rocker arm as it is running, if the sound/tone would change. Have you tried a stethoscope? Are the springs in good shape?

 

If more pressure quiets it down, that would mean I need more preload right?

And valve springs are brand new also, came with the cam kit I got, and I installed them myself. Nothing obvious was wrong with them

 

How long ago did you the the original swap? Did it do it before? Is it worse cold or warmed up? Are all push rods straight? (rolled them on the wife's kitchen counters?) If it were me, I would get in a little stethoscope time, even a long screwdriver will work.

 

Original rebuild was about 20k miles ago, been clacking for about 19k of those miles. The recent rebuild was give or take 3k miles ago, which is when I swapped from melling stock lifters to Hughes 5007s. Pushrods are straight, also currently have the 5th set of pushrods in there messing with different preloads.

Its somewhat noticeable cold, gets worse as it warms up, but the volume levels out after it gets to a certain temp. It hasn’t gotten worse the whole time it’s been making the sound, and it doesn’t care about load, ONLY rpm.