Update...
WHISTLING NOISE - I just happened to bump into an expert at the motor parts store earlier, who had a good look/listen at my Carb and said the whistling noise is literally coming from the carb internals itself, just normally sucking it's air, and it's perfectly normal... I'm curious to know what others on this forum think about that? I'm still skeptical myself, as I've never heard a carb have a "normal" whistling type noise at idle/high vac, but I'm no expert...
The original issue I posted here actually returned with a vengeance today, after disappearing/not happening at all yesterday. So, I decided I would high tail it to the parts store and maybe try changing out the leads, as when I grabbed the coil lead I got an almighty zap!... Anyways, long story short, after swapping out the coil lead, and just for the fun of it, the ballast resistor, the issues seems to have gone/hibernating again... So, lets see what the nexrt few days of testing brings, especially Wednesday as I will attempt a 80km round trip via freeway driving!
On another note, I have noticed my coil is getting exceptionally hot, so tomorrow I will try and modify the mounting bracket on the intake manifold, so that the coil sits vertically VS horizontally, and perhaps incorporate a thermal "break" to alleviate as much heat transmission as possible!
Another issue I have realised is that when declining, or on level ground, if I brake suddenly/hard enough I can make the vehicle stall. However, this seems not to be the case if climbing... I checked float levels and they seem spot on... Any thoughts? thanks again, and will update as we go!