I have ran the carbs both ways and have not had a issue. BUT if i was to make any change it would be to go with a center hung float. that makes for less float slush issue either holding the needle close or having it held open and flooding the motor. BUT with me leaveing the line NO less then 5000 rpm and pretty much pulling the front wheels off the ground I have not ran into either problem with running the carbs at 90degrees.Some also feel that running them 90degree has a better fuel distribution.
But again like i said In MY case I seen no difference either way.
So i would say mount it an test it and set it up which ever way works best for you.
God doesn't like ugly.
