If you are really keen on them, they are kinda popular in the USA and you could have a look here: http://www.lcengineering.com/
They specialise in performance parts for everything Toyota 22R
I know for a fact they have downdraft and sidedraft webber kits for the 22R motor, but they are VERY costly for what performance u gain i think, when you convert prices......
no worries. somehow a couple of years ago i got signed up for their newsletter and i still get it monthly in my email.. Kinda interesting but all so costly for a single-cam engine...
I just wish they had lists for the 18R-G series ........
autobarn should be able to find you the kit for you i asked about it a while ago and they can get it... theyc an also get 480 holley for the 22r to ither 420 or 480 i dont remember