If using the SU needle program to work out what needle you need it doesn't seem to ask if you have single or twin carbs. If it does then i'm blind.
Does anyone know how to work this out if you have twin 1 1/2" SU's ?
What needles are you people running that have similar engines to mine.
I have a 1275, 12g940 head sligtly ported, quite lumpy cam ( not sure of size ),
S type extractors and 1 3/4" exhaust

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76 1275 Leyland S

David Vizards book : Tuning BL's A Series Engine , gives a bit of a guide . A 1275 S with 2 x11/2 SU's + modified head + semi race cam uses red springs and No 3 or 4 needles . A 1275 S with 2x 11/2 SU's + modified head + full race cam + extractors uses blue or red springs and BG needles . Use it as a starting point and have the engine dyno tuned is the best way , take along a few different needles

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1965 Morris 850
1966 Morris Mini Minor
1967 Morris Cooper 'S'
1977 Leyland LS

MK2 Cooper S in Oz with the Police pack had twin HS4s and Ramflo filters.
Standard needles were CP4.
I find #6 needle is better, A/F ratio is spot on 13:1 all the way up.
Motor is a 1293A+, Tighe 270* cam, ported head, C/R 9.4:1, Corolla 1.5:1 rockers and Perry 3-1 freeflow manifold.

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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.

Thanks guys,
I will try #6 and see how it goes.
I'm not sure of compression ratio but told not standard and engine bored out to 1310.
Rockers are not standard either. They are solid and about 1/2 " wide and not sure of ratio.

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76 1275 Leyland S

That sounds like the POS later sintered type, used on everything from ~75 on.
They are only around 1.24:1 and don't even have bushes in them.

Best stock factory rockers for a 1310 are the earlier 1275 pressed metal type with oval pads. They are ~1.3:1.

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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.