Ah, the reason I ask, is that the earliest ones were held on with a large brass nut, in which the intake port and carburettor mount simply met rather than interlocking, the brass nut was simply a nut and bolt that had a sleeve in the middle, when the nut was tightened the sleeve gripped the intake and the carby, and held them next to each other.
Similar in function to the plastic nut that holds a pedestal fan at height.
As you can imagine, this was a pretty ridiculous system, and it took very little use for the nut to shave free, casing the carby to come loose, which resulted in some pretty poor running.
In many cases people would drill a hole in the side of the nut, and tap it, then insert a grub screw to fix the nut in place.
However, in most cases they simply went back to the repair shop, which resulted in a new carby being fitted, an updated model with a reliable mounting system. The old brass nut carburettors were then generally discarded by the shop, and now, they have become a most prized possession.
Up until the late 60's, Victa used slide carburettors, all but one (the 3Q) were based on, and resembled the original Victa carby, there was the 3F, the 3L and the 3S, the only differences were the mount size of the first two, and the 3S was for 160cc engines, none of them had a Jet needle.
The 3Q had a plastic slide, which was molded to better control the flow through, but still no Jet needle.
To my knowledge, the only time Victa ever used it was on the Industrial version of the 3F/L/S series carburettors, and those industrials are not easy to find.
In the late 60's they went to the G2, and then the G3 both butterfly carburettors, that were governed by an air vane mounted on the carby itself (Victa took a while to try governing again, after their bizarre and failed attempt at doing so with the "Automatic) these carburettors are more effective in my opinion, particularly the G3.
After that, came the Mid 70's introduction of the plastic G4, which is governed by a vacuum line to a diaphragm, the design was updated to the LM in the early 80's, which had some slight modifications, and that one is still in use today.
