I just searched on tech again and found quotes from 0.015 to 0.120, with 0.060-0.100 being most common. Most people agree that more preload will be quieter. I may give the 7.350" pushrods a go.

I still don't know why the #7 exhaust valve is sitting lower than the rest. It's very concerning.

https://ls1tech.com/forums/search.php?searchid=20002481

 

Here is something that will make all the "LS7" lifter fanatics say Wth?, the LS7 style lifter with enclosed roller was first used in the Buick 3.8 engine. Lol

My engine has the the 3.8 type lifters or LS7 as many of us call them, using 7.4 push rods and zero noise.

 

.060-.080" preload is what I shoot for. Less preload will give you noisy valvetrain.

 

To much can also cause issues. The plunger will hit the inside of the tappet, stress the rod/rockers ect.


I would wait for a few more opinions on this before you go tearing into it, but to me it doesn't sound like a bearing or a rod.. Or rather then swap all, just stick a longer rod in the ones you think are making the noise. does it get any louder if you listen to that side of the engine by the valve cover?

 

Rather than search the internet or read LS1 I used a checker to confirm the correct push rod length rather than just do what everyone else does.

If you have one valve stem lower then the rest there is a good chance at some point the engine floated the valves and bent that one. Use a bore scope and see if that piston has artificial valve reliefs.

 

Here is the artificial valve reliefs haha

 

Pulled the oil drain plug real quick, absolutely nothing on it.

Hooked a mechanical oil pressure gauge up and it read 40 psi at warm idle, about 10psi less than what the dash gauge was reading.

Gonna get a leakdown tester soon and try that. Then maybe give longer pushrods a go, at least on the noisy cylinders first.

I wish I had a borescope to look for possible PTV damage.

 

That is no where near enough lift to have any PTVC issues. People have went a **** load bigger with more mill, had zero issues.

 

PTV can be caused by high RPM if the valve springs don't close the valves fast enough. The pic I posted happened with a .525 lift cam.

 

I'm still on the stock limiter (6k I think), and haven't missed a shift. Only been to redline a handful of times. I guess PTV is still an option but I will label it as unlikely for now. Maybe if the cam was off a tooth or two. but it was dot-to-dot, even took a picture for peace of mind