The Opel Admiral A and the Chevrolet Chevelle aren't close relatives, but our Czech friend and Tatra reviewer BobAsh drives one that wouldn't look (or sound) out of place doing gnarly burnouts in the Dairy Queen parking lot.
It looks quite American, though the hints of Ford Falcon-ness in its lines indicate that Opel designers didn't limit themselves to purely GM influences. Admiral buyers could get a 283-cubic-inch Chevrolet small-block V8 and Powerglide right from the factory, and that's what's important. Bob has done a full writeup (in Czech) for Autíčkář, and here's the English summary:
It's a 1966 Opel Admiral, powered by 283 Chevy (non numbers matching, but factory engine for that model), with 200R4 (hot rodded a little) behind it. Cool little hot rod that I can actually park downtown where I live now, wonderfully loud with the glasspacks and quite fast. Traded it for the 1968 Galaxie I had, with a guy from Hungary (so I now drive around a German hot rod with American engine on Hungarian plates in Czech Republic... I guess I need to add something French or British.