Complex sentence: This meant that Oldsmobile heads would go on Buick blocks, but not vice versa, and that changing the compression ratio on an Oldsmobile 215 required changing the heads, but on a Buick 215, only the pistons, which was less expensive and simpler.
Split into simpler sentences: This meant that Oldsmobile heads would go on Buick blocks, but not vice versa. Changing the compression ratio on an Oldsmobile 215 required changing the heads, but on a Buick 215, only the pistons, which was less expensive and simpler.