Sorry if this has been answered somewhere but whats the difference between a Local Chapter and an Affiliated Club?
Quite a bit of difference.
Local Chaters - or "LC's" are "Full blown USLMRA", they run USLMRA classes and rules. All racers at LC races are required to be USLMRA members. LC's also hold events at temporary venues, such as Fairs & Festivals, other motorsports events, etc. They are the Local representatives of the USLMRA. The USLMRA holds its Local Chapters to a bit higher standards than AC's
Affiliated Clubs are more of the "home track" type of clubs. They have a permanent facility, althought they may run USLMRA classes, they are allowed to write their own rule book, so long as it is approved by the USLMRA. USLMRA memberhsip is not required
by the USLMRA, however the AC itself may make requirements such as membership. The USLMRA AC program allows those tracks and racers that may not be running to USLMRA Regulations to enjoy some of the benefits that the USLMRA offers to their Local Chapters.
Both the LC's and The AC's are important parts of the USLMRA - Neither is "less" or "more" than the other, simply two different programs so that the USLMRA can include all racers.