XXX booster kit

developed in the early nineties for improving the performance 

of the stock venturi

improved engine performance in HP, fuel economy, emissions 

and drive ability

and a discount if you purchase the extension screw kit

oh why not, I've already spent a small fortune in money and time on this piece of shit carb

I noticed that my mate Ray's holley carb had something similar to the booster kit as fitted which is  probably why Bob calls it a 'proven product in the 

automotive industry'. 

Also notice the smaller holes in the tube which I guess deliver fuel as fine spray. Similar I guess to the yost power tube which sits in the original main jet tube body, that I've bloody tried already in a vain attempt to get the crappy carb to perform like one would expect!
The package arrived two weeks ago after the Trip Out, decided I had to sort out the jetting on my carb first though, having waded through a load of bullshit on the web, about not fitting small jets, I've just watched S&S fit a 66 main jet to a dyna glide tuning it on their dyno...