Strange noise - fixed

Ok sorry if the title is a bit vague. I currently own a 57 s max. Bought it cheap and came with a few problems, slowly working my way through them. But today I replaced my suspected faulty EGR valve. Only with a cheap used one to see if it made a difference. But on a test run, the engine is making a kind of "parade whistle" (warble whistle) noise that seems to follow the boost and vacuum stages of the engine running ?? It's quite loud from the outside. I will post a short vid tomorrow of the noise. I'm not sure if the original EGR was fooked and fitting this one has revealed a leak else where ?? It's just the type of noise is really odd. I've done all sorts of internet searches and nothing comes close to the noise I'm getting. I was just wondering if anyone had any ideas ?? Ok it should be this link, the last one was my daughter at Christmas:-/  https://drive.google.com/file/d/1sj7h9u21aoD3Cmg4fLT6vGAXzotnINN6/view?usp=drivesdk