Back in the 70s and early 80s there was an AMA rule book event for biplane sport aerobatics.

I went to a few events - bipes only. It was blast. Most guys showed up with Aeromasters and the like. If you were flying a pulsar, acrostar, or skybolt, you were a notch above everyone else. I had an Acrostar (airtronics offered a kit for quite a while). That with the then "new" OS FSR engine was foridable.

I also flew my .40 size Pitts at one event, because the bipe event had a "Scale" bonus. Worked out ok until it got windy late in the day