The Rover engine, which is still being produced, is the 215 aluminum Buick engine that was used on '61-'63 Specials, Olds F-85, and Pontiac Tempest. The V-6 was based on this engine as a replacement when GM sold the tooling to Rover. GM then sold the V-6 tooling to Kaiser for use in Jeep products, after tooling up a cast iron V-8 based on the V-6. In the '70s, during the "gas crisis", GM scrambled to get the V-6 tooling back from Jeep, which had been bought out by AMC by then. Unfortunatly, GM ended up retooling the engine, as the original tooling had been filled with concrete and used as filler in a plant floor by AMC. Ironic, aint it. By the way, very little, if any, parts from the Rover engine will work with the 300,340,350 Buick small block. I do beleive that the moderd efi intake will fit on the original 215 though.
The big block Buicks differ from the small block mainly in deck hight and cylider casting thickness. Otherwise they are very similar, unlike other makes small and big blocks.
By the way- oldblu, your Regal has a Chevy engine, the Buick V-8 was dicontinued in '76. For the most part, by the early '80s the small block Chevy had become the standard "corporate" engine in most of GMs products, with the 307" Old hanging on to the late '80s.
