Matt,
I checked out my box of SU bits and pieces and found that the only significant difference is in the float chamber lids. I was wrong about the different height float chambers. There are differences in the float chambers but they do not relate to the type of float but rather the way the float chamber is mounted to the body.
The needle and seat assembly bodies are the same length irrespective of the type and size of needle.
The lids come in 2 basic types and the significant difference is in the depth of the recess that the needle and seat assembly screws into. On float lids that originally had brass floats, when the assembly is screwed into place the needle seat body should be inline with the centreline of the float pivot pin. On later type plastic float lids the needle seat body is approx 3/32" below the centreline of the float pivot pin.
As you said the lid appeared to be short so it is the original brass float lid. This should use either the brass float or the 1st type plastic float I mentioned previously. Sounds like you are using the wrong type of plastic float. The 1st type has only one bend in the metal arm and it is at the pivot point end. From the pivot point it drops vertically down approx 3/32" and then runs horizontally to the float. This puts the needle and seat in the correct position in relation to the float arm. It basically follows the same shape as the original metal arm it replaces.
The 2nd type float, which looks as though this is the one you have, runs horizontally from the pivot point and then has a 2 bend dog leg where the float is attached. If you use this float with the 1st type lid then the needle and seat will protrude too far and will not be in the correct position for the float.
Part No cast into the top of the lid is AUC 8452 for the brass float lid.
Part No cast into the UNDERSIDE of the lid is AUD2276 or AUD 2277 for the plastic float lids. There are other numbers cast or etched into the top of the lid depending on whether it is a single inlet position type Part No AUD9203 or a multiple inlet position casting where the inlet pipe can be set up in different positions. These may have cast numbers or etched numbers on the top of the lid.
These are the numbers on the lids I have. There are many different lid configurations. 18 different types are listed in the SUMIDEL catalogue. I don?t know which ones are for brass or plastic floats as its based on the cars the lids were originally fitted to.
PartNos for the floats as listed in the SUMIDEL catalogue are:
Brass float WZX1301
1st type metal arm plastic float to replace brass float ? not listed
2nd type metal dog leg arm plastic float WZX1304
3rd type all plastic float WZX1300
In regard to other numbers there are LH and RH bodies and these bodies come in 2 types. Bodies that have solid mounted float chambers and bodies that can have variable angle solid or flexible mount float chambers. The float chambers and bodies for the 2 types of bodies are different as the variable angle/flexible mount type has to accommodate an adaptor.
Part No for HS2 LH solid mount body is AUC8450 and float chamber is AUC1390
Part No for LH variable angle/solid/flexible mount is AUC1341 and RH AUC1342. Float chamber is AUC1310.
These are Part Nos of the bits I have but there are most likely many others. LH is with float chamber on left when looking into intake/aircleaner side of carb.
I am sure if you contact SU Midel they will be only too pleased to assist you.
Address is 4 Frazer St Lakemba 2195
They have a web site too but it doesn?t have a lot of info.
I was in Sydney recently and called in to see about some refurbishment work and they were most helpful. The chap who does a lot of the work is over 70 and just loves SUs. He?s been there for 30 or 40 years.
Good Luck
Regards
RonR
