Is 75deg too cool for the RV8? Today, whilst out I noticed on the emerald software(monitoring for other reason) that after a blat down a local a road that the temp was at 74deg. Of course it soon picked up when I slowed down.
Unless you have a 74ish degree stat in there then I would say your stat is jammed open. At higher road speed the engine is over cooling because the stat is not closing and preserving the temp in the engine.