Hello flashstang04 and welcome.
The stock 260 flat top SU carbs are not very good.
Don’t waste any time on them, try to find some earlier round top SU`s or possibly some Webers.
The stock 260 E88 cly head is an emissions head and not good for any performance mods.
Don’t know what your plans are, stay with an L-series motor or a V-8 or other swap but you will find all the info you need here.
Please use the search feature, a lot of your questions have already been asked and answered.
Other than that, the 260 model (1 year production) is a good platform to build from.