I'll call it aerodynamic since it has fenders.
The XR-6
The Concept That Started it All
Leroi Tex Smith writer Ed Kania photographer Sep 1, 2005
I remember this well. I even had a slant six once, but it wasn't an aluminum block like this one. The main takeaway at the time was that Triumph disc brakes (and therefore wire wheels) fit a VW front end.
The body was concieved as fiberglass, bankrolled as aluminum by others, then finally handed to George Barris. Who proceeded to slather it in lead, so it must have been steel. OTOH Gene Winfield learned to work in aluminum just to make the fenders.
Overall it's considered the exemplar for it's disc brakes, coilovers and side-draft Webers on a hot rod at that time. Won AMBR, bettered anything Roth could do.