XK's Unlimited has a solid plastic replacement that might be better than the hollow original. I have it in one of my carbs for a few years now . I did get one from them though where one one float was not bonded securely to the metal piece and it could move a little side to side and drag against the brass plug so I did not use that one and still have a hollow float in the other carb.
David Barnes
68 E-Type FHC