diff --git a/src/d_main.c b/src/d_main.c
index db0f74fb2..e28dc1c5c 100644
--- a/src/d_main.c
+++ b/src/d_main.c
@@ -892,13 +892,7 @@ void D_StartTitle(void)
 
 			if (server)
 			{
-				char mapname[6];
-
-				strlcpy(mapname, G_BuildMapName(spstage_start), sizeof (mapname));
-				strlwr(mapname);
-				mapname[5] = '\0';
-
-				COM_BufAddText(va("map %s\n", mapname));
+				COM_BufAddText(va("map %s\n", G_BuildMapName(spstage_start)));
 			}
 		}
 
diff --git a/src/d_netcmd.c b/src/d_netcmd.c
index 6ff12ce3b..5c7705a42 100644
--- a/src/d_netcmd.c
+++ b/src/d_netcmd.c
@@ -2347,8 +2347,7 @@ void D_MapChange(INT32 mapnum, INT32 newgametype, boolean pencoremode, boolean r
 	if (delay != 2)
 	{
 		UINT8 flags = 0;
-		const char *mapname = G_BuildMapName(mapnum);
-		I_Assert(W_CheckNumForName(mapname) != LUMPERROR);
+		I_Assert(W_CheckNumForName(G_BuildMapName(mapnum)) != LUMPERROR);
 		buf_p = buf;
 		if (pencoremode)
 			flags |= 1;
@@ -2363,7 +2362,7 @@ void D_MapChange(INT32 mapnum, INT32 newgametype, boolean pencoremode, boolean r
 		// new gametype value
 		WRITEUINT8(buf_p, newgametype);
 
-		WRITESTRINGN(buf_p, mapname, MAX_WADPATH);
+		WRITEINT16(buf_p, mapnum);
 	}
 
 	if (delay == 1)
@@ -2791,7 +2790,6 @@ static void Command_Map_f(void)
   */
 static void Got_Mapcmd(UINT8 **cp, INT32 playernum)
 {
-	char mapname[MAX_WADPATH+1];
 	UINT8 flags;
 	INT32 resetplayer = 1, lastgametype;
 	UINT8 skipprecutscene, FLS;
@@ -2833,7 +2831,7 @@ static void Got_Mapcmd(UINT8 **cp, INT32 playernum)
 
 	FLS = ((flags & (1<<3)) != 0);
 
-	READSTRINGN(*cp, mapname, MAX_WADPATH);
+	mapnumber = READINT16(*cp);
 
 	if (netgame)
 		P_SetRandSeed(READUINT32(*cp));
@@ -2841,7 +2839,7 @@ static void Got_Mapcmd(UINT8 **cp, INT32 playernum)
 	if (!skipprecutscene)
 	{
 		DEBFILE(va("Warping to %s [resetplayer=%d lastgametype=%d gametype=%d cpnd=%d]\n",
-			mapname, resetplayer, lastgametype, gametype, chmappending));
+			G_BuildMapName(mapnumber), resetplayer, lastgametype, gametype, chmappending));
 		CON_LogMessage(M_GetText("Speeding off to level...\n"));
 	}
 
@@ -2861,13 +2859,12 @@ static void Got_Mapcmd(UINT8 **cp, INT32 playernum)
 		CV_StealthSetValue(&cv_playercolor[0], players[0].skincolor);
 	}
 
-	mapnumber = M_MapNumber(mapname[3], mapname[4]);
 	LUAh_MapChange(mapnumber);
 
 	demo.savemode = (cv_recordmultiplayerdemos.value == 2) ? DSM_WILLAUTOSAVE : DSM_NOTSAVING;
 	demo.savebutton = 0;
 
-	G_InitNew(pencoremode, mapname, resetplayer, skipprecutscene, FLS);
+	G_InitNew(pencoremode, mapnumber, resetplayer, skipprecutscene, FLS);
 	if (demo.playback && !demo.timing)
 		precache = true;
 	if (demo.timing)
diff --git a/src/dehacked.c b/src/dehacked.c
index a467543e9..1aaa2f2c8 100644
--- a/src/dehacked.c
+++ b/src/dehacked.c
@@ -1684,7 +1684,7 @@ static const struct {
 
 #define MAXFLICKIES 64
 
-static void readlevelheader(MYFILE *f, INT32 num)
+static void readlevelheader(MYFILE *f, char * name)
 {
 	char *s = Z_Malloc(MAXLINELEN, PU_STATIC, NULL);
 	char *word;
@@ -1692,10 +1692,24 @@ static void readlevelheader(MYFILE *f, INT32 num)
 	//char *word3; // Non-uppercase version of word2
 	char *tmp;
 	INT32 i;
+	const INT32 num = G_MapNumber(name);
+
+	if (num > NUMMAPS)
+	{
+		I_Error("Too many maps!");
+	}
+
+	if (mapheaderinfo[num-1])
+		G_SetGameModified(multiplayer, true); // only mark as a major mod if it replaces an already-existing mapheaderinfo
 
 	// Reset all previous map header information
 	P_AllocMapHeader((INT16)(num-1));
 
+	if (mapheaderinfo[num-1]->lumpname == NULL)
+	{
+		mapheaderinfo[num-1]->lumpname = Z_StrDup(name);
+	}
+
 	do
 	{
 		if (myfgets(s, MAXLINELEN, f))
@@ -1895,8 +1909,7 @@ static void readlevelheader(MYFILE *f, INT32 num)
 				// i.e., Nextlevel = AB, Nextlevel = FZ, etc.
 
 				// Convert to map number
-				if (word2[0] >= 'A' && word2[0] <= 'Z' && word2[2] == '\0')
-					i = M_MapNumber(word2[0], word2[1]);
+					i = G_MapNumber(word2);
 
 				mapheaderinfo[num-1]->nextlevel = (INT16)i;
 			}
@@ -1911,8 +1924,7 @@ static void readlevelheader(MYFILE *f, INT32 num)
 				// i.e., MarathonNext = AB, MarathonNext = FZ, etc.
 
 				// Convert to map number
-				if (word2[0] >= 'A' && word2[0] <= 'Z' && word2[2] == '\0')
-					i = M_MapNumber(word2[0], word2[1]);
+					i = G_MapNumber(word2);
 
 				mapheaderinfo[num-1]->marathonnext = (INT16)i;
 			}
@@ -3608,10 +3620,7 @@ static void reademblemdata(MYFILE *f, INT32 num)
 				// i.e., Level AB, Level FZ, etc.
 
 				// Convert to map number
-				if (word2[0] >= 'A' && word2[0] <= 'Z')
-					value = M_MapNumber(word2[0], word2[1]);
-
-				emblemlocations[num-1].level = (INT16)value;
+				emblemlocations[num-1].level = (INT16)G_MapNumber(word2);
 			}
 			else if (fastcmp(word, "SPRITE"))
 			{
@@ -3836,10 +3845,7 @@ static void readunlockable(MYFILE *f, INT32 num)
 					// i.e., Level AB, Level FZ, etc.
 
 					// Convert to map number
-					if (word2[0] >= 'A' && word2[0] <= 'Z')
-						i = M_MapNumber(word2[0], word2[1]);
-
-					unlockables[num].variable = (INT16)i;
+					unlockables[num].variable = (INT16)G_MapNumber(word2);
 				}
 				else
 					deh_warning("Unlockable %d: unknown word '%s'", num+1, word);
@@ -3930,11 +3936,7 @@ static void readcondition(UINT8 set, UINT32 id, char *word2)
 		PARAMCHECK(1);
 		ty = UC_MAPVISITED + offset;
 
-		// Convert to map number if it appears to be one
-		if (params[1][0] >= 'A' && params[1][0] <= 'Z')
-			re = M_MapNumber(params[1][0], params[1][1]);
-		else
-			re = atoi(params[1]);
+		re = G_MapNumber(params[1]);
 
 		if (re < 0 || re >= NUMMAPS)
 		{
@@ -3948,11 +3950,7 @@ static void readcondition(UINT8 set, UINT32 id, char *word2)
 		ty = UC_MAPTIME;
 		re = atoi(params[2]);
 
-		// Convert to map number if it appears to be one
-		if (params[1][0] >= 'A' && params[1][0] <= 'Z')
-			x1 = (INT16)M_MapNumber(params[1][0], params[1][1]);
-		else
-			x1 = (INT16)atoi(params[1]);
+		x1 = (INT16)G_MapNumber(params[1]);
 
 		if (x1 < 0 || x1 >= NUMMAPS)
 		{
@@ -4160,12 +4158,7 @@ static void readmaincfg(MYFILE *f)
 				// i.e., Level AB, Level FZ, etc.
 
 				// Convert to map number
-				if (word2[0] >= 'A' && word2[0] <= 'Z')
-					value = M_MapNumber(word2[0], word2[1]);
-				else
-					value = get_number(word2);
-
-				spstage_start = spmarathon_start = (INT16)value;
+				spstage_start = spmarathon_start = (INT16)G_MapNumber(word2);
 			}
 			else if (fastcmp(word, "SPMARATHON_START"))
 			{
@@ -4173,12 +4166,7 @@ static void readmaincfg(MYFILE *f)
 				// i.e., Level AB, Level FZ, etc.
 
 				// Convert to map number
-				if (word2[0] >= 'A' && word2[0] <= 'Z')
-					value = M_MapNumber(word2[0], word2[1]);
-				else
-					value = get_number(word2);
-
-				spmarathon_start = (INT16)value;
+				spmarathon_start = (INT16)G_MapNumber(word2);
 			}
 			else if (fastcmp(word, "SSTAGE_START"))
 			{
@@ -4186,12 +4174,7 @@ static void readmaincfg(MYFILE *f)
 				// i.e., Level AB, Level FZ, etc.
 
 				// Convert to map number
-				if (word2[0] >= 'A' && word2[0] <= 'Z')
-					value = M_MapNumber(word2[0], word2[1]);
-				else
-					value = get_number(word2);
-
-				sstage_start = (INT16)value;
+				sstage_start = (INT16)G_MapNumber(word2);
 				sstage_end = (INT16)(sstage_start+7); // 7 special stages total plus one weirdo
 			}
 			else if (fastcmp(word, "SMPSTAGE_START"))
@@ -4200,12 +4183,7 @@ static void readmaincfg(MYFILE *f)
 				// i.e., Level AB, Level FZ, etc.
 
 				// Convert to map number
-				if (word2[0] >= 'A' && word2[0] <= 'Z')
-					value = M_MapNumber(word2[0], word2[1]);
-				else
-					value = get_number(word2);
-
-				smpstage_start = (INT16)value;
+				smpstage_start = (INT16)G_MapNumber(word2);
 				smpstage_end = (INT16)(smpstage_start+6); // 7 special stages total
 			}
 			else if (fastcmp(word, "REDTEAM"))
@@ -4294,12 +4272,7 @@ static void readmaincfg(MYFILE *f)
 				// i.e., Level AB, Level FZ, etc.
 
 				// Convert to map number
-				if (word2[0] >= 'A' && word2[0] <= 'Z')
-					value = M_MapNumber(word2[0], word2[1]);
-				else
-					value = get_number(word2);
-
-				titlemap = (INT16)value;
+				titlemap = (INT16)G_MapNumber(word2);
 				titlechanged = true;
 			}
 			else if (fastcmp(word, "HIDETITLEPICS") || fastcmp(word, "TITLEPICSHIDE"))
@@ -4440,12 +4413,7 @@ static void readmaincfg(MYFILE *f)
 				// i.e., Level AB, Level FZ, etc.
 
 				// Convert to map number
-				if (word2[0] >= 'A' && word2[0] <= 'Z')
-					value = M_MapNumber(word2[0], word2[1]);
-				else
-					value = get_number(word2);
-
-				bootmap = (INT16)value;
+				bootmap = (INT16)G_MapNumber(word2);
 				//titlechanged = true;
 			}
 			else if (fastcmp(word, "TUTORIALMAP"))
@@ -4454,12 +4422,7 @@ static void readmaincfg(MYFILE *f)
 				// i.e., Level AB, Level FZ, etc.
 
 				// Convert to map number
-				if (word2[0] >= 'A' && word2[0] <= 'Z')
-					value = M_MapNumber(word2[0], word2[1]);
-				else
-					value = get_number(word2);
-
-				tutorialmap = (INT16)value;
+				tutorialmap = (INT16)G_MapNumber(word2);
 			}
 			else
 				deh_warning("Maincfg: unknown word '%s'", word);
@@ -4859,24 +4822,7 @@ static void DEH_LoadDehackedFile(MYFILE *f, boolean mainfile)
 				}
 				else if (fastcmp(word, "LEVEL"))
 				{
-					// Support using the actual map name,
-					// i.e., Level AB, Level FZ, etc.
-
-					// Convert to map number
-					if (word2[0] >= 'A' && word2[0] <= 'Z')
-						i = M_MapNumber(word2[0], word2[1]);
-
-					if (i > 0 && i <= NUMMAPS)
-					{
-						if (mapheaderinfo[i])
-							G_SetGameModified(multiplayer, true); // only mark as a major mod if it replaces an already-existing mapheaderinfo
-						readlevelheader(f, i);
-					}
-					else
-					{
-						deh_warning("Level number %d out of range (1 - %d)", i, NUMMAPS);
-						ignorelines(f);
-					}
+					readlevelheader(f, word2);
 				}
 				else if (fastcmp(word, "GAMETYPE"))
 				{
diff --git a/src/doomdef.h b/src/doomdef.h
index 9c4664135..5c89053cb 100644
--- a/src/doomdef.h
+++ b/src/doomdef.h
@@ -625,7 +625,7 @@ extern const char *compdate, *comptime, *comprevision, *compbranch;
 
 /// Backwards compatibility with musicslots.
 /// \note	You should leave this enabled unless you're working with a future SRB2 version.
-#define MUSICSLOT_COMPATIBILITY
+//#define MUSICSLOT_COMPATIBILITY
 
 /// Experimental attempts at preventing MF_PAPERCOLLISION objects from getting stuck in walls.
 //#define PAPER_COLLISIONCORRECTION
diff --git a/src/doomstat.h b/src/doomstat.h
index 629e5cead..91ca7b0ea 100644
--- a/src/doomstat.h
+++ b/src/doomstat.h
@@ -324,7 +324,7 @@ typedef struct
   */
 typedef struct
 {
-	// The original eight, plus one.
+	char * lumpname;       ///< Lump name can be really long
 	char lvlttl[22];       ///< Level name without "Zone". (21 character limit instead of 32, 21 characters can display on screen max anyway)
 	char subttl[33];       ///< Subtitle for level
 	char zonttl[22];       ///< "ZONE" replacement name
@@ -415,6 +415,7 @@ typedef struct
 #define LF2_VISITNEEDED   (1<<3) ///< Not available in Time Attack modes until you visit the level
 
 extern mapheader_t* mapheaderinfo[NUMMAPS];
+extern INT32 nummapheaders;
 
 // This could support more, but is that a good idea?
 // Keep in mind that it may encourage people making overly long cups just because they "can", and would be a waste of memory. 
diff --git a/src/f_finale.c b/src/f_finale.c
index 4355cf231..d127a2359 100644
--- a/src/f_finale.c
+++ b/src/f_finale.c
@@ -1837,9 +1837,6 @@ void F_StartTitleScreen(void)
 		titlemapcameraref = NULL;
 		gamemap = titlemap;
 
-		if (!mapheaderinfo[gamemap-1])
-			P_AllocMapHeader(gamemap-1);
-
 		maptol = mapheaderinfo[gamemap-1]->typeoflevel;
 		globalweather = mapheaderinfo[gamemap-1]->weather;
 
diff --git a/src/g_demo.c b/src/g_demo.c
index 50c53d1c3..a841afa9e 100644
--- a/src/g_demo.c
+++ b/src/g_demo.c
@@ -3021,7 +3021,7 @@ void G_DoPlayDemo(char *defdemoname)
 	R_ExecuteSetViewSize();
 
 	P_SetRandSeed(randseed);
-	G_InitNew(demoflags & DF_ENCORE, G_BuildMapName(gamemap), true, true, false); // Doesn't matter whether you reset or not here, given changes to resetplayer.
+	G_InitNew(demoflags & DF_ENCORE, gamemap, true, true, false); // Doesn't matter whether you reset or not here, given changes to resetplayer.
 
 	for (i = 0; i < MAXPLAYERS; i++)
 	{
diff --git a/src/g_game.c b/src/g_game.c
index 0151783e9..bd6d7f713 100644
--- a/src/g_game.c
+++ b/src/g_game.c
@@ -185,6 +185,7 @@ struct quake quake;
 
 // Map Header Information
 mapheader_t* mapheaderinfo[NUMMAPS] = {NULL};
+INT32 nummapheaders;
 
 // Kart cup definitions
 cupheader_t *kartcupheaders = NULL;
@@ -644,20 +645,14 @@ void G_SetGameModified(boolean silent, boolean major)
 		Command_ExitGame_f();
 }
 
-/** Builds an original game map name from a map number.
-  * The complexity is due to MAPA0-MAPZZ.
+/** Returns the map lump name for a map number.
   *
   * \param map Map number.
-  * \return Pointer to a static buffer containing the desired map name.
-  * \sa M_MapNumber
+  * \return Map name.
+  * \sa G_MapNumber
   */
 const char *G_BuildMapName(INT32 map)
 {
-	static char mapname[10] = "MAPXX"; // internal map name (wad resource name)
-
-	I_Assert(map >= 0);
-	I_Assert(map <= NUMMAPS);
-
 	if (map == 0) // hack???
 	{
 		if (gamestate == GS_TITLESCREEN)
@@ -669,19 +664,35 @@ const char *G_BuildMapName(INT32 map)
 		map = G_RandMap(G_TOLFlag(cv_newgametype.value), map, false, 0, false, NULL)+1;
 	}
 
-	if (map < 100)
-		sprintf(&mapname[3], "%.2d", map);
+	if (map > 0 && map <= NUMMAPS && mapheaderinfo[map - 1] != NULL)
+	{
+		return mapheaderinfo[map - 1]->lumpname;
+	}
 	else
 	{
-		mapname[3] = (char)('A' + (char)((map - 100) / 36));
-		if ((map - 100) % 36 < 10)
-			mapname[4] = (char)('0' + (char)((map - 100) % 36));
-		else
-			mapname[4] = (char)('A' + (char)((map - 100) % 36) - 10);
-		mapname[5] = '\0';
+		return NULL;
+	}
+}
+
+/** Returns the map number for map lump name.
+  *
+  * \param name Map name;
+  * \return Map number.
+  * \sa G_BuildMapName
+  */
+INT32 G_MapNumber(const char * name)
+{
+	INT32 map;
+
+	for (map = 0; map < nummapheaders; ++map)
+	{
+		if (strcasecmp(mapheaderinfo[map]->lumpname, name) == 0)
+		{
+			break;
+		}
 	}
 
-	return mapname;
+	return map + 1;
 }
 
 /** Clips the console player's mouse aiming to the current view.
@@ -4318,7 +4329,7 @@ cleanup:
 // Can be called by the startup code or the menu task,
 // consoleplayer, displayplayers[], playeringame[] should be set.
 //
-void G_DeferedInitNew(boolean pencoremode, const char *mapname, INT32 pickedchar, UINT8 ssplayers, boolean FLS)
+void G_DeferedInitNew(boolean pencoremode, INT32 map, INT32 pickedchar, UINT8 ssplayers, boolean FLS)
 {
 	INT32 i;
 	UINT16 color = SKINCOLOR_NONE;
@@ -4350,18 +4361,17 @@ void G_DeferedInitNew(boolean pencoremode, const char *mapname, INT32 pickedchar
 		CV_StealthSetValue(&cv_playercolor[0], color);
 	}
 
-	if (mapname)
-	{
-		D_MapChange(M_MapNumber(mapname[3], mapname[4]), gametype, pencoremode, true, 1, false, FLS);
-	}
+	D_MapChange(map, gametype, pencoremode, true, 1, false, FLS);
 }
 
 //
 // This is the map command interpretation something like Command_Map_f
 //
 // called at: map cmd execution, doloadgame, doplaydemo
-void G_InitNew(UINT8 pencoremode, const char *mapname, boolean resetplayer, boolean skipprecutscene, boolean FLS)
+void G_InitNew(UINT8 pencoremode, INT32 map, boolean resetplayer, boolean skipprecutscene, boolean FLS)
 {
+	const char * mapname = G_BuildMapName(map);
+
 	INT32 i;
 
 	(void)FLS;
@@ -4427,7 +4437,7 @@ void G_InitNew(UINT8 pencoremode, const char *mapname, boolean resetplayer, bool
 		return;
 	}
 
-	gamemap = (INT16)M_MapNumber(mapname[3], mapname[4]); // get xx out of MAPxx
+	gamemap = map;
 
 	// gamemap changed; we assume that its map header is always valid,
 	// so make it so
@@ -4455,7 +4465,7 @@ void G_InitNew(UINT8 pencoremode, const char *mapname, boolean resetplayer, bool
 	{
 		char *title = G_BuildMapTitle(gamemap);
 
-		CON_LogMessage(va(M_GetText("Map is now \"%s"), G_BuildMapName(gamemap)));
+		CON_LogMessage(va(M_GetText("Map is now \"%s"), mapname));
 		if (title)
 		{
 			CON_LogMessage(va(": %s", title));
@@ -4705,12 +4715,12 @@ INT32 G_FindMapByNameOrCode(const char *mapname, char **realmapnamep)
 
 	if (mapnamelen == 2)/* maybe two digit code */
 	{
-		if (( newmapnum = M_MapNumber(mapname[0], mapname[1]) ))
+		if (( newmapnum = G_MapNumber(mapname) ))
 			usemapcode = true;
 	}
 	else if (mapnamelen == 5 && strnicmp(mapname, "MAP", 3) == 0)
 	{
-		if (( newmapnum = M_MapNumber(mapname[3], mapname[4]) ))
+		if (( newmapnum = G_MapNumber(mapname) ))
 			usemapcode = true;
 	}
 
diff --git a/src/g_game.h b/src/g_game.h
index 78812a72c..78dddb1a3 100644
--- a/src/g_game.h
+++ b/src/g_game.h
@@ -81,8 +81,8 @@ extern consvar_t cv_resume;
 #define MAXPLMOVE (50)
 #define SLOWTURNTICS (6)
 
-// build an internal map name MAPxx from map number
 const char *G_BuildMapName(INT32 map);
+INT32 G_MapNumber(const char *mapname);
 
 void G_BuildTiccmd(ticcmd_t *cmd, INT32 realtics, UINT8 ssplayer);
 
@@ -123,7 +123,7 @@ extern INT32 localaiming[MAXSPLITSCREENPLAYERS]; // should be an angle_t but sig
 void G_ChangePlayerReferences(mobj_t *oldmo, mobj_t *newmo);
 void G_DoReborn(INT32 playernum);
 void G_PlayerReborn(INT32 player, boolean betweenmaps);
-void G_InitNew(UINT8 pencoremode, const char *mapname, boolean resetplayer,
+void G_InitNew(UINT8 pencoremode, INT32 map, boolean resetplayer,
 	boolean skipprecutscene, boolean FLS);
 char *G_BuildMapTitle(INT32 mapnum);
 
@@ -161,7 +161,7 @@ void G_SpawnPlayer(INT32 playernum);
 
 // Can be called by the startup code or M_Responder.
 // A normal game starts at map 1, but a warp test can start elsewhere
-void G_DeferedInitNew(boolean pencoremode, const char *mapname, INT32 pickedchar,
+void G_DeferedInitNew(boolean pencoremode, INT32 map, INT32 pickedchar,
 	UINT8 ssplayers, boolean FLS);
 void G_DoLoadLevel(boolean resetplayer);
 
diff --git a/src/lua_baselib.c b/src/lua_baselib.c
index 0ee1a7a02..8fe7a73f9 100644
--- a/src/lua_baselib.c
+++ b/src/lua_baselib.c
@@ -2387,6 +2387,7 @@ static int lib_sChangeMusic(lua_State *L)
 
 #else
 	const char *music_name = luaL_checkstring(L, 1);
+	UINT32 position, prefadems, fadeinms;
 	boolean looping = (boolean)lua_opttrueboolean(L, 2);
 	player_t *player = NULL;
 	UINT16 music_flags = 0;
diff --git a/src/m_menu.c b/src/m_menu.c
index 7f6f542c6..32d82f8f6 100644
--- a/src/m_menu.c
+++ b/src/m_menu.c
@@ -7767,7 +7767,7 @@ static void M_StartGrandPrix(INT32 choice)
 
 	G_DeferedInitNew(
 		false,
-		G_BuildMapName(grandprixinfo.cup->levellist[0] + 1),
+		grandprixinfo.cup->levellist[0] + 1,
 		(UINT8)(cv_chooseskin.value - 1),
 		(UINT8)(cv_splitplayers.value - 1),
 		false
@@ -8066,7 +8066,7 @@ static void M_ChooseTimeAttack(INT32 choice)
 	else
 		G_RecordDemo(nameofdemo);
 
-	G_DeferedInitNew(false, G_BuildMapName(cv_nextmap.value), (UINT8)(cv_chooseskin.value-1), 0, false);
+	G_DeferedInitNew(false, cv_nextmap.value, (UINT8)(cv_chooseskin.value-1), 0, false);
 }
 
 static void M_HandleStaffReplay(INT32 choice)
diff --git a/src/m_misc.c b/src/m_misc.c
index 4f9190b4c..cd8a35cba 100644
--- a/src/m_misc.c
+++ b/src/m_misc.c
@@ -168,32 +168,6 @@ boolean takescreenshot = false; // Take a screenshot this tic
 
 moviemode_t moviemode = MM_OFF;
 
-/** Returns the map number for a map identified by the last two characters in
-  * its name.
-  *
-  * \param first  The first character after MAP.
-  * \param second The second character after MAP.
-  * \return The map number, or 0 if no map corresponds to these characters.
-  * \sa G_BuildMapName
-  */
-INT32 M_MapNumber(char first, char second)
-{
-	if (isdigit(first))
-	{
-		if (isdigit(second))
-			return ((INT32)first - '0') * 10 + ((INT32)second - '0');
-		return 0;
-	}
-
-	if (!isalpha(first))
-		return 0;
-	if (!isalnum(second))
-		return 0;
-
-	return 100 + ((INT32)tolower(first) - 'a') * 36 + (isdigit(second) ? ((INT32)second - '0') :
-		((INT32)tolower(second) - 'a') + 10);
-}
-
 // ==========================================================================
 //                         FILE INPUT / OUTPUT
 // ==========================================================================
diff --git a/src/m_misc.h b/src/m_misc.h
index cfcd0f3f7..4e597adc2 100644
--- a/src/m_misc.h
+++ b/src/m_misc.h
@@ -42,8 +42,6 @@ void M_StopMovie(void);
 // the file where game vars and settings are saved
 #define CONFIGFILENAME "kartconfig.cfg"
 
-INT32 M_MapNumber(char first, char second);
-
 boolean FIL_WriteFile(char const *name, const void *source, size_t length);
 size_t FIL_ReadFileTag(char const *name, UINT8 **buffer, INT32 tag);
 #define FIL_ReadFile(n, b) FIL_ReadFileTag(n, b, PU_STATIC)
diff --git a/src/p_saveg.c b/src/p_saveg.c
index 0b083e42c..8f2575f07 100644
--- a/src/p_saveg.c
+++ b/src/p_saveg.c
@@ -4381,7 +4381,7 @@ boolean P_LoadGame(INT16 mapoverride)
 		return false;
 
 	// Only do this after confirming savegame is ok
-	G_DeferedInitNew(false, G_BuildMapName(gamemap), savedata.skin, 0, true);
+	G_DeferedInitNew(false, gamemap, savedata.skin, 0, true);
 	COM_BufAddText("dummyconsvar 1\n"); // G_DeferedInitNew doesn't do this
 
 	return true;
diff --git a/src/p_setup.c b/src/p_setup.c
index 50f39c5fa..4a50e2d08 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -427,8 +427,10 @@ void P_AllocMapHeader(INT16 i)
 	if (!mapheaderinfo[i])
 	{
 		mapheaderinfo[i] = Z_Malloc(sizeof(mapheader_t), PU_STATIC, NULL);
+		mapheaderinfo[i]->lumpname = NULL;
 		mapheaderinfo[i]->flickies = NULL;
 		mapheaderinfo[i]->grades = NULL;
+		nummapheaders++;
 	}
 	P_ClearSingleMapHeaderInfo(i + 1);
 }
@@ -4473,7 +4475,7 @@ boolean P_AddWadFile(const char *wadfilename)
 			INT16 num;
 			if (name[5]!='\0')
 				continue;
-			num = (INT16)M_MapNumber(name[3], name[4]);
+			num = (INT16)G_MapNumber(name);
 
 			// we want to record whether this map exists. if it doesn't have a header, we can assume it's not relephant
 			if (num <= NUMMAPS && mapheaderinfo[num-1])
diff --git a/src/s_sound.c b/src/s_sound.c
index a7d45e160..f17d5bdd2 100644
--- a/src/s_sound.c
+++ b/src/s_sound.c
@@ -2665,8 +2665,8 @@ static void Command_Tunes_f(void)
 		tunearg = mapheaderinfo[gamemap-1]->musname;
 		track = mapheaderinfo[gamemap-1]->mustrack;
 	}
-	else if (!tunearg[2] && toupper(tunearg[0]) >= 'A' && toupper(tunearg[0]) <= 'Z')
-		tunenum = (UINT16)M_MapNumber(tunearg[0], tunearg[1]);
+	else if (isalpha(tunearg[0]))
+		tunenum = (UINT16)G_MapNumber(tunearg);
 
 	if (tunenum && tunenum >= 1036)
 	{
diff --git a/src/w_wad.c b/src/w_wad.c
index 6de3cae6a..76f68d10f 100644
--- a/src/w_wad.c
+++ b/src/w_wad.c
@@ -65,7 +65,7 @@
 #ifdef SCANTHINGS
 #include "p_setup.h" // P_ScanThings
 #endif
-#include "m_misc.h" // M_MapNumber
+#include "g_game.h" // G_MapNumber
 
 #ifdef HWRENDER
 #include "hardware/hw_main.h"
@@ -278,7 +278,7 @@ static inline void W_LoadDehackedLumps(UINT16 wadnum, boolean mainfile)
 			const char *name = lump_p->name;
 			if (name[0] == 'M' && name[1] == 'A' && name[2] == 'P' && name[5]=='\0')
 			{
-				INT16 mapnum = (INT16)M_MapNumber(name[3], name[4]);
+				INT16 mapnum = (INT16)G_MapNumber(name);
 				P_ScanThings(mapnum, wadnum, lump + ML_THINGS);
 			}
 		}