Just wanted to post this - found that #121 orings fit the oring slot for the cylinder head to carb boots almost perfectly. Not sure if it is posted elsewhere or not.
Use viton or nitrile orings. Amazon has a set of 5 viton #121 for $1.19. You may be able to find them even cheaper locally.
Just wanted to put it out there. It may be common knowledge, but I searched and couldn't find it.
