World Formula and LO206 are certainly different classes.  Both are based around the same block, but the WF makes about 5hp more than a LO206 (which is around 10).  LO206 is a hand built, sealed Briggs Animal, and the WF  has a few upgrades that make the extra power.  You could probably use the same chassis and just swap the engines out, but you’ll need 2 engines if you want to run in both classes.

This topic will probably interest you.

https://new.ekartingnews.com/forums/topic/switching-between-lo206-and-world-formula/

You absolutely can use all of the same stuff. The only thing that might be different is rear tire size. A lot of people run 6″ rears in 206. We run 7.10 in world formula in the nhka.

A few of us from nhka that race world formula are also thinking of heading to Rock Island to race in the 206 class