wierd vibration sound from Holly Sniper LS Intake

[88Stanger]

So, I got my LS running good. Interesting little thing happened. When the engine is running there is a really weird sound, almost like a bearing is going out in say the Alt. or pulley until you lay your hand on the intake and "Poof" the sound stops completely. Must be one of the stupidest things I have experienced in a long time. It is just crazy. I know that some will say why worry about it, but it just bugs the ever living crap out of me!! So it must go away.
I have thought about trying sound deadener (Generic form of Dynomat) as I have extra. The other idea is to make some kind of a "brace" from maybe one of the bolts on the each valve cover up and over the intake and put a rubber grommet or ??? between that and the intake top.
Anyone every have this issue or fixed it?
Thanks for any responses.

[Daaaanz67]

Try running it without the belt on just to eliminate the accessories. Maybe vibration from accessories radiating tho the intake. Is there a factory plastic cover over the intake? If so take it off maybe a missing rubber insulator.

[akdg87]

are you running an aftermarket throttle body? 92 MM? They have really bad IAC passages which will make that sound until it warms up a bit.

[Overdriven]

I’ve heard of other unlikely things vibrating and creating weird noises, an intake manifold is a first. I assume you have the Sniper without the removable top plate. That would be too easy as you could weld some small braces to the underside to stiffen the cover and stop it from vibrating.

Something to consider. Maybe make a logo and have it cut into or out of a plate and weld that to the top of the manifold to stiffen the top plate. It could look better than a brace but probably the most expensive option especially if you have a black manifold and want to refinish it. Can’t hurt to contact Holley and see if they’re willing to do anything.

[1957 Chief]

When I had a similar sheet metal intake on my 5.3, it amplified the valvetrain noise so much that I was scared to run it, exactly as you describe. My good friend is the head of GPI here in Arkansas and he told me it was normal with those sheet metal intakes. I ran it for over a year and no issues.

Sorry no help, but maybe a little bit of reassurance that all is well.

Bubba

[sweetk30]

possible cure for this since your hand made it go away is a strip of dyna mat under the bottom side to hide it but do the same effect as your hand . ? ? worth a shot .