You have to call their 800 order line, and tell them you want main jets for a Dellorto (or Weber) and then specify the size. They'll ship you whatever you want. They're cheap enough that you should get a set of 135's and a set of 130's and play a little.
You should also order their Weber or Dellorto *whichever you have) "Super Performance Book" so you'll know how to diagnose problems and set them up properly.
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