Editing Chevrolet big-block engine (section)

===Commercial applications===
Mark IV engines saw extensive application in Chevrolet and GMC medium duty trucks, as well as in [[Blue Bird Corporation]]'s [[Blue Bird All American|All American]] and [[TC/2000]] transit buses (the latter up until 1995, using a 427 with purpose-built carburetor). In addition to the 427, a {{cvt|366|cuin|L|1}} version was produced for the commercial market. Both the 366 and 427 commercial versions were built with a raised-deck, four-bolt main bearing cap cylinder to accommodate an extra oil control ring on the pistons. Unfortunately, the raised deck design complicated the use of the block in racing applications, as standard intake manifolds required spacers for proper fit. Distributors with adjustable collars that allowed adjustments to the length of the distributor shaft also had to be used with 366 and 427 truck blocks. These engines can be modified for performance use with different length rods, pistons, and/or crank throws, but it's typically deemed easier and more cost effective to use readily available 454 and 502 displacement standard blocks for performance use.

Mark IV engines also found themselves widely used in power boats. Many of these engines were ordinary Chevrolet production models that were fitted with the necessary accessories and drive system to adapt them to marine propulsion. [[Mercury Marine]], in particular, was a major user of the Mark IV in marine drives, and relabeled the engines with their corporate logo.