Is a chip needed with a pulley swap?
Usually, yes. For an upper pulley swap, with a pulley smaller than 3.2 you should at the very least get a dyno pull with a wideband A/F check. In general, you want the A/F ratio to be below 12.0 (12 parts air to 1 part fuel). Some people have run as small as a 2.93 pulley without any noticeable detonation (including the author of this document), but it is important to have the A/F checked just in case.
