|The Maximum Mayhem Dungeons™ Series of modules are based on the OSRIC™ System (Old-school System Reference and Index Compilation) which is very similar to the first edition of Advanced Dungeons and Dragons or 1e.
Converting Dark Wizard Modules to D&D 5e: WotC Coversions to 5th Edition PDF
Converting early D&D to Pathfinder Pathfinder OGL Conversion Guide
Converting Stats for use with Savage Worlds: Converting other RPGs to Savage Worlds
Stat Conversions for DCC: DCC Quick Monster Stats
Understanding THAC0: Retro RPG Library - THAC0 Explained