put in gt40 manifold

could just be the throttle body. mine whistles a little right when i give it gas but not at idle.

A small amount of "whistling" is normal with the GT40 intake from my personal experience as well as what I've heard on here. Some of it could be coming from your throttle body as well depending on brand and size. Really if it were coming from the back of the lower intake it would be leaking oil not making noises. One way to narrow it down is to use penetrating oil while the engine is running and spray the suspected area. If the noise stops, there's your problem. Should it be the lower, the best way is to take it back off and fix it right the first time, no real "half-ass" way to do it if you know what I mean. Besides, that really isn't one of the tougher tasks on these cars compared to the projects most of us get ourselves involved in. You'll find out.....

Mine whistles too. I don't have a leak becuase I've had the thing off twice since installation, and it still does it. It is only noticeable when I punch it though. If you read the reviews on stangnet for GT-40 intakes you'll see that other people say thier's whistles too. As for the supercharger, I'd get at least heads and if you wanna get best results, a cam. If you're not looking to go to radical with your setup, go E-cam. My freind had an A-trim, E-cam, Cobra intake, and full xhaust. The setup worked well, unfortunately his freind put it into a gully @ about 70. I have the same exact setup as you except for my MSD ignition and I still have a stock throttle body, as well as 3:55's. I ran a 13.9 at the track last summer.

Mine whistles when you punch it. But yeah if you had a leak at the back of the manifold where the cork gasket goes it wouldn't whistle you would have an oil leak

i have a stock throttle body with gt40 intake, no whistle.

My Explorer intake (same family as the GT40) doesn't whistle.

Here's a wild card to explore. How is your pcv hooked up? Do you have the hose connected between the valve cover and the throttle body? If you capped those off as many do, then at idle, when the engine is pulling lots of vacuum, the intake is 'pulling' hard on the crankcase. If the valve cover vent is blocked off or that line is gummed up, then the whistling you hear could be the sound of air entering the crankcase through where ever your weakest link is - perhaps the lower intake end seals; perhaps the front crank seal or even the rear main. At idle you're basically pulling a vacuum on the crankcase, and that air has to allowed to enter from some place. It's suppose to come from the valve cover vent via the throttle body - so it's been through the maf. But if those are blocked off, other people have posted about whistling phenomena that went away once they properly vented the crankcase. If you have an issue here, I'd want to get it resolved before I put a supercharger on there.

I had one on my 95 and it whistled alot at idle.

Mines been whistleing for 10 years. Had it off and reinstalled it 4 or 5 times. Still whistles but works great.

Michael Yount said:

My Explorer intake (same family as the GT40) doesn't whistle.

Click to expand...

Might be because the Explorer and Cobra are cast, and therefore thicker than the fabricated tubing of the GT40. Thinner material=more sound. Just an idea..........