I'd run a filter on that Won't last long running it without one...

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Lillee - 1969 Morris Mini K

Go the full rebuild and include an antivibration spacer. Stops fuel froth and the knock on effects.

seeing you've got a "air box" you could go a longer manifold and junk that swan neck one

The 4 numbers are there for matching purposes and you'll find on factory cars with the twin setup they run sequentially. For minis it doesnt matter

A fundemental thing to understand is that carb is really 2 carbs in one body. They share a common fuel bowl and a very similar so your settings on the tuning side should be very similar or something is wrong.

Finally put a cover plate between you and the carb. It wont effect carb performance but might save your life (unless your after a darwin award)

I wouldn't call that manifold of yours a `swan neck' (THAT acronym is reserved for the tall Lynx one and others you can't see thru....)
If you want to improve it heaps, just port it out. At least you have room in there now for a nice K&N filter..
Open it out to add volume and increase its cross section, mainly in the bottom half.
I can recommend Des Hammill's book `How to power tune the BMC/BL/Rover 1275 A series engine'. Has pics. $39.95 at www.pitstop.net.au

I use a Redline 3005 one, which when stock used to flow 137CFM. After a fair bit of work with the die grinder it flowed 188. It is probably ~200 now that I've attacked it more since, using GR's suggestions.

By comparison, the best new one about now (GR's) flows 240CFM... which is probably only of extra benefit on a race car, which mine is not.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.