Moreover, in the mid-1980s, hot rodders discovered the 215 could be stretched to as much as , using the Buick 300 crankshaft, new cylinder sleeves, and an assortment of non-Buick parts. It could also be fitted with high-compression cylinder heads from the Morgan +8. Using the 5-litre Rover block and crankshaft, a displacement of is possible and used primarily in racing applications, stretching the design to its limits it is possible to achieve displacements of over and possibly even displacements near of , though the latter has not been tested in practice as of yet.