360 vacuum leak.
Well I didn't want to run it like that but I was trying to see if my vacuum leak went away if I either (A) just ran two opposite breathers, or (B) ran it with pcv one side and breather on the other. I couldn't do option b because I had nothing to plug the breather hole with at the time. I'm just confused by the outcome because I've seen engines run with just the two breathers.
The reason that the PCV and breather are on opposite sides is so that, as the PCV sucks up the blow-by fumes, Fresh air, comes in thru the breather on that opposite side. If the breather was on the same side, then the PCV would just suck the fresh air in and out, and the CC fumes would just stay where the are.
The thing is, if you already have a lot of blow-by, maybe the PCV cannot get rid of it all.
If you look at the picture that Rusty provided, you will see a breather hose going from the air-cleaner house to the breather. This provides clean filtered air to the breather under most circumstances. But when, like at WOT, the PCV system cannot keep up, then the excess blow-by, backs up the breather hose and into the filter housing, and the engine gobbles it up anyhow. By routing the breather hose to the clean side of the filter house, excess blow-by gasses do not oil-up your airfilter.
To make your engine idle the best that it can; Try this;
Reset your Idle timing to in the window of 8 to 12 degrees, then;
reset the mixture screws to in the middle of their range, make sure the secondaries are fully closed but not sticking; then adjust the speed screw to provide the rest of the fuel from the transfers.
If the idle speed gets to be too fast, retard the timing. Repeat as often as necessary until you have your engine idling as smooth as is possible, at whatever idle speed it likes in the window of about 550>700 in gear, with the idle-timing ending up in the range of say 10 to 12 degrees. Then fine tune the Idle mixture, with a minor mixture screw adjustment.
If this is not willing to happen, THEN go look for a vacuum leak.
This will get you very close.
With a stock cam or a modest cam;
setting the idle-timing to a high number like more than 16>20*, is, in most cases, a sure fire way to screw up your low rpm Part-throttle fuel-delivery curve, and often introduces an off idle-stumble, that you might want to try and cure with accelerator pump-shot. For a street driven car, this is not a good idea. That extra gas will cost you at the pump, on every fill-up. And honestly, the sag is easily cured with properly working transfers. The first time your engine actually cares about Power-timing, is at convertor stall. There is no ideal Idle-Timing. Well there might be, but without EFI, it will be impossible to drive it off the line. This is because the number will climb to over 25 degrees, possibly as high as 35; but to get that, and to still idle in the window, the throttle will have to be nearly closed, and then, to get the gas, the mixture screws may have to be adjusted to the max. Ok now, just try to put it into gear, and drive off like that, It's Not gonna happen.