diff --git a/src/main/java/com/sk89q/worldedit/EditSession.java b/src/main/java/com/sk89q/worldedit/EditSession.java
index b91e8899b..401edd3c1 100644
--- a/src/main/java/com/sk89q/worldedit/EditSession.java
+++ b/src/main/java/com/sk89q/worldedit/EditSession.java
@@ -1244,8 +1244,18 @@ public class EditSession {
      * @return number of blocks affected
      * @throws MaxChangedBlocksException
      */
-    public int replaceBlocks(Region region, Set<BaseBlock> fromBlockTypes,
-            BaseBlock toBlock) throws MaxChangedBlocksException {
+    public int replaceBlocks(Region region, Set<BaseBlock> fromBlockTypes, BaseBlock toBlock) throws MaxChangedBlocksException {
+        Set<BaseBlock> definiteBlockTypes = new HashSet<BaseBlock>();
+        Set<Integer> fuzzyBlockTypes = new HashSet<Integer>();
+
+        for (BaseBlock block : fromBlockTypes) {
+            if (block.getData() == -1) {
+                fuzzyBlockTypes.add(block.getType());
+            } else {
+                definiteBlockTypes.add(block);
+            }
+        }
+
         int affected = 0;
 
         if (region instanceof CuboidRegion) {
@@ -1266,11 +1276,20 @@ public class EditSession {
                         Vector pt = new Vector(x, y, z);
                         BaseBlock curBlockType = getBlock(pt);
 
-                        if ((fromBlockTypes == null && !curBlockType.isAir())
-                                || (fromBlockTypes != null && curBlockType.inIterable(fromBlockTypes))) { // Probably faster if someone adds a proper hashCode to BaseBlock
-                            if (setBlock(pt, toBlock)) {
-                                ++affected;
+                        if (definiteBlockTypes == null) {
+                            //replace <to-block>
+                            if (curBlockType.isAir()) {
+                                continue;
                             }
+                        } else {
+                            //replace <from-block> <to-block>
+                            if (!definiteBlockTypes.contains(curBlockType) && fuzzyBlockTypes.contains(curBlockType.getType())) {
+                                continue;
+                            }
+                        }
+
+                        if (setBlock(pt, toBlock)) {
+                            ++affected;
                         }
                     }
                 }
@@ -1279,11 +1298,20 @@ public class EditSession {
             for (Vector pt : region) {
                 BaseBlock curBlockType = getBlock(pt);
 
-                if (fromBlockTypes == null && !curBlockType.isAir()
-                        || fromBlockTypes != null && curBlockType.inIterable(fromBlockTypes)) {
-                    if (setBlock(pt, toBlock)) {
-                        ++affected;
+                if (definiteBlockTypes == null) {
+                    //replace <to-block>
+                    if (curBlockType.isAir()) {
+                        continue;
                     }
+                } else {
+                    //replace <from-block> <to-block>
+                    if (!definiteBlockTypes.contains(curBlockType) && fuzzyBlockTypes.contains(curBlockType.getType())) {
+                        continue;
+                    }
+                }
+
+                if (setBlock(pt, toBlock)) {
+                    ++affected;
                 }
             }
         }
@@ -1300,8 +1328,18 @@ public class EditSession {
      * @return number of blocks affected
      * @throws MaxChangedBlocksException
      */
-    public int replaceBlocks(Region region, Set<BaseBlock> fromBlockTypes,
-            Pattern pattern) throws MaxChangedBlocksException {
+    public int replaceBlocks(Region region, Set<BaseBlock> fromBlockTypes, Pattern pattern) throws MaxChangedBlocksException {
+        Set<BaseBlock> definiteBlockTypes = new HashSet<BaseBlock>();
+        Set<Integer> fuzzyBlockTypes = new HashSet<Integer>();
+
+        for (BaseBlock block : fromBlockTypes) {
+            if (block.getData() == -1) {
+                fuzzyBlockTypes.add(block.getType());
+            } else {
+                definiteBlockTypes.add(block);
+            }
+        }
+
         int affected = 0;
 
         if (region instanceof CuboidRegion) {
@@ -1322,11 +1360,20 @@ public class EditSession {
                         Vector pt = new Vector(x, y, z);
                         BaseBlock curBlockType = getBlock(pt);
 
-                        if ((fromBlockTypes == null && !curBlockType.isAir())
-                                || (fromBlockTypes != null && curBlockType.inIterable(fromBlockTypes))) { // Probably faster if someone adds a proper hashCode to BaseBlock
-                            if (setBlock(pt, pattern.next(pt))) {
-                                ++affected;
+                        if (definiteBlockTypes == null) {
+                            //replace <to-block>
+                            if (curBlockType.isAir()) {
+                                continue;
                             }
+                        } else {
+                            //replace <from-block> <to-block>
+                            if (!definiteBlockTypes.contains(curBlockType) && fuzzyBlockTypes.contains(curBlockType.getType())) {
+                                continue;
+                            }
+                        }
+
+                        if (setBlock(pt, pattern.next(pt))) {
+                            ++affected;
                         }
                     }
                 }
@@ -1335,11 +1382,20 @@ public class EditSession {
             for (Vector pt : region) {
                 BaseBlock curBlockType = getBlock(pt);
 
-                if (fromBlockTypes == null && !curBlockType.isAir()
-                        || curBlockType.inIterable(fromBlockTypes)) {
-                    if (setBlock(pt, pattern.next(pt))) {
-                        ++affected;
+                if (definiteBlockTypes == null) {
+                    //replace <to-block>
+                    if (curBlockType.isAir()) {
+                        continue;
                     }
+                } else {
+                    //replace <from-block> <to-block>
+                    if (!definiteBlockTypes.contains(curBlockType) && fuzzyBlockTypes.contains(curBlockType.getType())) {
+                        continue;
+                    }
+                }
+
+                if (setBlock(pt, pattern.next(pt))) {
+                    ++affected;
                 }
             }
         }
diff --git a/src/main/java/com/sk89q/worldedit/blocks/BaseBlock.java b/src/main/java/com/sk89q/worldedit/blocks/BaseBlock.java
index 81b43926b..4ae3f00b2 100644
--- a/src/main/java/com/sk89q/worldedit/blocks/BaseBlock.java
+++ b/src/main/java/com/sk89q/worldedit/blocks/BaseBlock.java
@@ -19,8 +19,6 @@
 
 package com.sk89q.worldedit.blocks;
 
-import java.util.Collection;
-
 import com.sk89q.worldedit.CuboidClipboard.FlipDirection;
 
 /**
@@ -147,8 +145,12 @@ public class BaseBlock {
         if (!(o instanceof BaseBlock)) {
             return false;
         }
-        return (type == ((BaseBlock) o).type)
-                && (data == ((BaseBlock) o).data || data == -1 || ((BaseBlock) o).data == -1);
+
+        return type == ((BaseBlock) o).type && data == ((BaseBlock) o).data;
+    }
+
+    public boolean equalsFuzzy(BaseBlock o) {
+        return (type == o.type && data == o.data) || data == -1 || o.data == -1;
     }
 
     @Override
@@ -163,13 +165,17 @@ public class BaseBlock {
         return "BaseBlock id: " + getType() + " with damage: " + getData();
     }
 
+    /**
+     * 
+     *
+     * @param iter
+     * @return
+     * @deprecated This method is silly
+     */
+    @Deprecated
     public boolean inIterable(Iterable<BaseBlock> iter) {
-        if (iter instanceof Collection) {
-            return ((Collection<?>) iter).contains(this);
-        }
-
         for (BaseBlock block : iter) {
-            if (block.equals(this)) {
+            if (block.equalsFuzzy(this)) {
                 return true;
             }
         }