Whistle noise around intake manifold???

I have a 350 out of a 68 wildcat. When the engine has ran for a while or is warmed up after i rev the engine it has a whistle noise. Its right after i let off it when its whining down in park. And when im driving and let off the gas its a constant noise when im rolling. Its not the PCV valve or the gromet its not the carb. I dont really know where its coming from. Vacum leak of some sort im guessing? Any ideas or help would be greatly appreciated I hate noises.ou:

 

Check the brake booster hose, especially the plastic part that does into the booster grommet. There is a check valve there that may whistle if plugged or bad. The hose may also have a small hole.

Mike

 

booster hose is knew and so is the grommet but the booster is a rebuild you think it might be defected?

 

The booster could have failed...... I would get a section of heater hose about 1 - 2ft long ...or something like that....put one end up to your ear and have someone rev the engine for you to make that noise and put the hose towards the noise.....that makes it much easier to find the exact location of it. Usually an inch or so either way.....best tool in the world.

 

I dont know if you ever got this whistle taken care of, but I thought I should let everyone else who may read this thread that, it may have been the intake gasket... easy test would be to take a can of carb cleaner, and spray around the perimeter of the intake gasket, and see if the idle picks up. If it does, then you have a leak. FYI.

 

FYI carb cleaner is FLAMABLE spray it around ,hit the exh mfld and you're going to get a BIG WHOOSH in your face.
Use a spray bottle of water, it will change the engine speed if there's a leak.

 

I was going to suggest spraying something around too (wd40 - it's not good for anything else).

 

Got to be careful with wd40 as well, parafin based. I just grab the nearby windex bottle.

 

How 'bout a squirt bottle full of gasoline! JK of couse!

 

A leak I ran into when I detailed my engine was with the thermostatically controlled choke. I dont remember a gasket when I took this part off the intake and didnt install one when I put it back after painting.

It whistled loud. In the picture you can see black carbon on the intake where it leaked. I used some gasket material I had and made a gasket. There wasnt one that came with my complete gasket kit.