18R-C Vacuum Leak

[LT2K]

Afternoon,
Please forgive me if it's already been covered but my car has a horrible suspected Vacuum Leak. The engine (18R-C) makes a noise that sounds like a air hose leaking constantly as the engine runs, the noise increases as engine speed increases.
The car runs fairly normal above 2000 RPM but will not idle properly and stalls when I depress the clutch (stopping at a red light usually).
I know a lot of the hoses are fairly bad condition but nothing has changed in the past 2-3 months and only the other day did the noise and running issues start. I took a bit of time and studied more of the hoses and found that some of the hoses were incorrectly connected since the installation of the 32/36. This made it run slightly better and a little bit smoother, it also idles at a more appropriate rpm (around 1100 and it isn't too bad...).
One thing that makes it hard to find is that the noise is just as loud all over the engine, I put my finger over a couple of small gaps that I thought may be leaking but they weren't.

One thing that may help in diagnoses is, I drove to Brisbane (from Sunshine Coast) on Saturday and got stuck in a little traffic jam (for unknown reasons...), it got a little hot at idle (near the orange bit) so I used the accelerator to idle at around 1500-2000 and it quickly cooled engine. It ran fine rest of the way down, during and back but later that night when I was dropping my girlfriend home, it started to idle roughly and run like balls, so I'm hoping I haven't done a gasket (hasn't been replaced since I have owned the vehicle since it had apparently had a service prior to purchase).

Ps. I'm unsure how much sense my post made but I hope you can interpret it and assist me, as much as possible as it has me clueless.

[LT2K]

Further investigations found that it was a stripped thread on the carby body for the Mixture Screw. Since has been drilled and reseated. I also fitted a spare 18R-C I had laying around over the weekend with my father.
There's quite some silly differences between a 79 18R-C and an 81 18R-C.