I'm running into a really bizarre problem and I know of no better place to pose it. I have a 1965 mustang with a previously rebuilt engine. It's stroked up to a 302, has a rolling valvetrain, Edelbrock timing gears (quiet version), Pertronix electronic ignition system (brand new), and ported heads from a '95. I recently changed the carburetor to a Holley 600 cfm #80457. I got it installed and running yesterday with the distributor hooked up to the distributor vacuum advance port on the carburetor, and the power brakes hooked up to the PCV/Power brake vacuum port.
I drove it around like this for most of yesterday before finally conceding that I needed to hook up the PCV port from the passenger's side valve cover to something. Today I dug out a carb spacer, installed it and got the unoccupied PCV port hooked up to it. However, when I went to go fire it up, the engine wasn't idling well, and there was an extremely loud high pitched whine coming from the engine, and the pitch and volume increased with higher RPMs. The noise seems to be coming from the distributor.
The other odd thing is once I increased the mixture and kicked up the idle speed, the engine is surging; that is, the RPMs are quickly going up, and slowly coming down again, over and over. I think I can attribute the idling issues to the carburetor simply needing tuning, but I don't want to rule out other issues.
My question is, does anybody have any other ideas where the noise may be coming from and most importantly why? The only thing I can come up with as a possibility is that the vacuum from the distributor is getting robbed by this new spacer.
And yes, there is proper oil pressure.
Sorry for the long post, I want to make sure I give as much information as possible. Any help would be greatly appreciated; thanks guys!
First of all, hello and thank you all for the quick response!
Veronica: I've attached a picture of what's attached. I'm pretty sure it's stock; it's been on the car since before I got it, and the rest of the car was untouched.
pcfrisch: It's a new spacer as well; I bought it, used it for a couple of days and took it off when I realized there was a nozzle on my Edelbrock that I could use in place of it.
EagleAutosports: The car's been running fine for a couple of months now, so I don't think it's an intake to head leak.
The noise isn't so much as a whistling as much as a whine, a lot like a supercharger would make. Much louder, though
I took another look, I don't see any places it could be leaking offhand. It's really hard to tell where the noise is coming from because it's so loud. It's also possible it's coming from the carburetor, but I couldn't imagine why it would be.
Ok, I thought you said whistle. I've had two gaskets split on me and cause a whistle, the first after 7 years and then the recent one after another 7 years.
Anyway, we'll keep helping out to find it.
And Veronica is the best here in the classic section, she's awesome.
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Sounds like something that happened to me, I connected the vent of the tappet cover to the vacuum at the base of the carb and got myself a whistle also.
If the problem is the same as mine then i think what you need to do is T the vent into the other tappet cover hose and send them both into the underside of the air cleaner.
I figured my problem was that full vacuum was being introduced to the motor and stressing the seals, these are not designed to cope with large ammounts of presure, either negative or positive. Perhaps the reason you can hear it from the dizzy is that this is the easiest place for the air to be drawn in, past the o-ring.
An easy way to check my theory on your car would be to block the hose that you are running from the tappet cover to the vacuum at the base of the carby.
Hi again. I've seen a couple of cars before that had freshly built motors that started making a really loud squealy kind of whistling noise that sort of sounded like a big time, really tight vacuum leak or belt squeal or something. What was happening was that, with the pcv hooked up and with either a non-vented driver's side filler cap, or a vacuum hose creating suction on that side also, the car would build up a monster vacuum in the crankcase and it would start sucking air past the rubber seal around the balancer. Made a dickens of a racket. One of the cars, the guy had taken it to several shops and nobody could figure out what it was. He finally brought it to where I was working and I sort of stumbled across the cause by accident. I thought at first it was a belt, so I started taking belts off and starting the car and letting it run briefly. It still made the noise with no belts at all. Then I went through the vacuum leak scenario, got the car to were I was certain that there were no vacuum leaks, but, it still made the noise. I took the balancer off to see if maybe it was the wrong balancer and the shaft was a bit too large or something, let the motor idle at low rpms and, no squeal. But, it was the right balancer. Then it dawned on me what was happening. An older motor won't hold vacuum anything near good enough to do that, but, a freshly built one, or a crate motor, like this particular one, would. Try starting the car, let it start making that noise, then unplug that hose from the driver's side valve cover. If that fixes the noise, you need to get a vented oil filler cap with no hose hooked to it. If not, we'll all ponder this thing a bit more, and see what we can come up with.
You know, I'm willing to bet anything that you guys are dead on. It would sure as heck explain the symptoms I'm "seeing". I'll test it as soon as I get home and let you know what I find. Thanks much!
Well, whaddya know? I unplugged the PCV hose going to the passenger valve cover from the cover and started up the engine. As soon as I did, I was greeted with the same familar squeal. As soon as I unplugged the hose from the spacer, the noise stopped and the engine promptly died.
At that point, enough was enough, so I removed the spacer from the equation. Of course it fired up just fine. So, presumably, the spacer was at fault. I've attached pictures for everyone's edification. I'll be hooking both PCV ports up to the air filter as recommended.
Thanks again to everyone for their quick and helpful responses! One of the things I really like about this place is that I not only get really useful solutions, but the logic behind them as well. You guys rock!
Loud high-pitched whine from engine 
One of the cars, the guy had taken it to several shops and nobody could figure out what it was. He finally brought it to where I was working and I sort of stumbled across the cause by accident. I thought at first it was a belt, so I started taking belts off and starting the car and letting it run briefly. It still made the noise with no belts at all. Then I went through the vacuum leak scenario, got the car to were I was certain that there were no vacuum leaks, but, it still made the noise. I took the balancer off to see if maybe it was the wrong balancer and the shaft was a bit too large or something, let the motor idle at low rpms and, no squeal. But, it was the right balancer. Then it dawned on me what was happening. An older motor won't hold vacuum anything near good enough to do that, but, a freshly built one, or a crate motor, like this particular one, would. Try starting the car, let it start making that noise, then unplug that hose from the driver's side valve cover. If that fixes the noise, you need to get a vented oil filler cap with no hose hooked to it. If not, we'll all ponder this thing a bit more, and see what we can come up with. 
