can any one tell me where to find the serial numbers on sidedraft dellortos

they are usually found on a small metal tag on each carby.
if they arent there you may be able to see where they once were held by a screw but snapped off.

so they only have a tag not numbers stamped on them like webbers

yeah im pretty sure as the dellortos i had both had a little metal tag with consecutive numbers stamped on.

I am looking at a pair to buy the only numbers on them are on the tags they are the same numbers I didnt now if it was a part number or serial number because they both match

All the dellorto's I have seen over the years only have it cast into the body but there are 2 main types. Early and late. A typical dellorto 40 will have DLHA40 cast into it and the late model will have an extra H at the end. DLHA40H. You want the earlier ones. They are much more suited to smaller ones than the later ones a the later carbs have slightly different progression ports that make it more difficult to tune down to your needs.