Did the steel Pinto air cleaner housing ever come with 30mm holes in the side of it? I'm guessing it's a back yard performance trick from back in the day 

Very much doubt it... 30mm only, I used to bore 40mm holes in mine across the back. It must've worked cause the filter had 4 circles of dirt when time to change it.
Edit.. I remember once I was trying for more carby noise so I cut the whole air cleaner housing back right up to the filter, didn't work well as the strength disappeared but sure got heads scratching at a car meet 😁

Should start a thread about forgotten mods we used to do in the good days of modifying these cars.. or doing a temporary fix that lasts for ever..

"Should start a thread about forgotten mods we used to do in the good days of modifying these cars.. or doing a temporary fix that lasts for ever.."
 
That will be a loooong thread.
 
These days seems to be ripping off any mods and chucking them, and going back to OEM. 

 
....water injection and a fist full of advance and endless fiddling with the advance springs.  :)

would electronic ignition fall into this category?
Scorcher  and luminition being changed back to oldschool points?
 
Maybe in a few years ITB's and bike carbs will go the way of skoggs, color coded dashs and sunroofs.
And why does every car have to have a 'tow'' seatbelt hanging off the front now?
 
 

Side pipes and Monaro rear spoilers, can't forget the 6ft cb antenna on the roof so when driving in low slung carparks the antenna scraps the ceiling like a Dodgem car !!

................ and filling the home-made pre-airfilter box with crushed ice to get more molecules down into the cylinders for more power on hot days !