what size su's would be best for 1200 ,would the hitachi be alright or the delorto.

CHEERS

hitachi su carbs come standard on the 1200 gx and i dont think dwllorto made su carbs

Are the hitachis different sizes or do you just change neddles etc .

i dare say you can cet diferent size hitachi su carbs but the ones to suit the 1200 are 38mm yes you can change the neddles to suit your tune.
i am not sure on wat size the hitachis on the 260z or the 1600 are the may be bigger. If you can get the origonal round top su carbs they are much better

how can you tell the difference between flat top and round top

thease are round tops



thease are flat tops

and this is a link you might find helpful
http://datsun1200.com/modules/nsections/index.php?op=viewarticle&artid=45#types

thanks for the help ,very apprieciated .



cheers