Might be worth a search of the TR Register forum. Quick search of 'carb needles' brought up lots of threads including this, which indicates that SM is the one recommended for all engine displacements
http://www.tr-register.co.uk/forums/index.php?/topic/47505-su-carbs/?hl=%2Bcarb+%2Bneedles#entry379185
(don't know why it hasn't come up as a link, it normally does when I copy and paste?)
Last edited by Malcolm T; 05/01/15 11:04 AM.
