Kinda there for tile entities, need to change actual block

src/main/java/com/colen/postea/API/TileEntityReplacementManager.java

@@ -0,0 +1,20 @@
+package com.colen.postea.API;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class TileEntityReplacementManager {
+
+    private static final Map<String, TileTransformer> replacementMap = new HashMap<>();
+
+    @SuppressWarnings("unused")
+    public static void addItemReplacement(String tileName , TileTransformer tileTransformer) {
+        replacementMap.put(tileName, tileTransformer);
+    }
+
+    @SuppressWarnings("unused")
+    public static TileTransformer getTileReplacementTransformer(String tileName) {
+        return replacementMap.getOrDefault(tileName, null);
+    }
+
+}

src/main/java/com/colen/postea/API/TileTransformer.java

@@ -0,0 +1,40 @@
+package com.colen.postea.API;
+
+import net.minecraft.item.Item;
+import net.minecraft.nbt.NBTTagCompound;
+import net.minecraft.tileentity.TileEntity;
+
+import java.util.Objects;
+import java.util.function.Function;
+
+public class TileTransformer {
+
+    private final Class<? extends TileEntity> tileClass;
+    private final Function<NBTTagCompound, NBTTagCompound> NBTModifierFunction;
+
+    public TileTransformer(Class<? extends TileEntity> tileClass, Function<NBTTagCompound, NBTTagCompound> NBTModifierFunction) {
+        this.tileClass = tileClass;
+        this.NBTModifierFunction = NBTModifierFunction;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (o == null) return false;
+        if (o instanceof TileTransformer that) {
+            return (this.tileClass == that.tileClass);
+        } else return false;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(tileClass);
+    }
+
+    public void modifyNBT(NBTTagCompound nbt) {
+        NBTModifierFunction.apply(nbt);
+    }
+
+    public Class<? extends TileEntity> getTileClass() {
+        return tileClass;
+    }
+}

src/main/java/com/colen/postea/Postea.java

@@ -2,10 +2,19 @@ package com.colen.postea;
 
 import com.colen.postea.API.BlockReplacementManager;
 import com.colen.postea.API.ItemStackReplacementManager;
+import com.colen.postea.API.TileEntityReplacementManager;
+import com.colen.postea.API.TileTransformer;
 import cpw.mods.fml.common.Mod;
 import cpw.mods.fml.common.event.FMLPreInitializationEvent;
+import net.minecraft.block.Block;
 import net.minecraft.init.Blocks;
 import net.minecraft.item.Item;
+import gregtech.api.GregTech_API;
+import net.minecraft.nbt.NBTTagCompound;
+import net.minecraft.tileentity.TileEntityChest;
+import net.minecraft.tileentity.TileEntityFurnace;
+
+import java.util.function.Function;
 
 @Mod(modid = Tags.MODID, version = Tags.VERSION, name = Tags.MODNAME, acceptedMinecraftVersions = "[1.7.10]")
 @SuppressWarnings("unused")
@@ -13,7 +22,17 @@ public class Postea {
 
     @Mod.EventHandler
     public void preInit(FMLPreInitializationEvent event) {
-        ItemStackReplacementManager.addItemReplacement(Item.getItemFromBlock(Blocks.grass), 0, Item.getItemFromBlock(Blocks.coal_ore), 10);
-        BlockReplacementManager.addBlockReplacement(Blocks.bedrock, 0, Blocks.wool, 2);
+        //ItemStackReplacementManager.addItemReplacement(Item.getItemFromBlock(Blocks.grass), 0, Item.getItemFromBlock(Blocks.coal_ore), 10);
+        BlockReplacementManager.addBlockReplacement(GregTech_API.sBlockOres1, 6, Blocks.emerald_ore, 0);
+        BlockReplacementManager.addBlockReplacement(GregTech_API.sBlockOres1, 16022, Blocks.nether_brick, 0);
+        BlockReplacementManager.addBlockReplacement(GregTech_API.sBlockOres1, 1018, Blocks.end_stone, 0);
+
+        // Define the transformation function
+        Function<NBTTagCompound, NBTTagCompound> myTransformer = (tag) -> {
+            return tag;
+        };
+
+        TileEntityReplacementManager.addItemReplacement("BlockController", new TileTransformer(TileEntityChest.class, myTransformer));
+
     }
 }

src/main/java/com/colen/postea/mixins/PosteaLoadingPlugin.java

@@ -46,6 +46,7 @@ public final class PosteaLoadingPlugin implements IEarlyMixinLoader, IFMLLoading
         mixins.add("MixinItemStack");
         mixins.add("MixinChunkProviderServer");
         mixins.add("MixinAnvilChunkLoader");
+        mixins.add("MixinTileEntity");
 
         return mixins;
     }

src/main/java/com/colen/postea/mixins/early/MixinAnvilChunkLoader.java

@@ -11,6 +11,7 @@ import org.spongepowered.asm.mixin.injection.Inject;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 
 @Mixin(AnvilChunkLoader.class)
+@SuppressWarnings("unused")
 public abstract class MixinAnvilChunkLoader {
 
     @Inject(
@@ -18,6 +19,7 @@ public abstract class MixinAnvilChunkLoader {
         at = @At("RETURN"),
         cancellable = true
     )
+    @SuppressWarnings("unused")
     private void onChunkReloadFromWorldSaveData(World world, NBTTagCompound compound, CallbackInfoReturnable<Chunk> cir) {
         Chunk chunk = cir.getReturnValue();
 

src/main/java/com/colen/postea/mixins/early/MixinChunkProviderServer.java

@@ -9,6 +9,7 @@ import org.spongepowered.asm.mixin.injection.Inject;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 
 @Mixin(ChunkProviderServer.class)
+@SuppressWarnings("unused")
 public class MixinChunkProviderServer {
 
     @Inject(
@@ -17,6 +18,7 @@ public class MixinChunkProviderServer {
         remap=false,
         cancellable = true
     )
+    @SuppressWarnings("unused")
     public void onChunkCreation(int chunkX, int chunkZ, CallbackInfoReturnable<Chunk> cir) {
         Chunk chunk = cir.getReturnValue();
 

src/main/java/com/colen/postea/mixins/early/MixinItemStack.java

@@ -15,6 +15,7 @@ import com.colen.postea.API.ItemStackKey;
 import com.colen.postea.API.ItemStackReplacementManager;
 
 @Mixin(ItemStack.class)
+@SuppressWarnings("unused")
 public abstract class MixinItemStack {
 
     @Shadow
@@ -23,6 +24,7 @@ public abstract class MixinItemStack {
     private Item field_151002_e;
 
     @Inject(method = "<init>(Lnet/minecraft/item/Item;II)V", at = @At("RETURN"))
+    @SuppressWarnings("unused")
     private void onConstructorReturn(Item item, int size, int metadata, CallbackInfo ci) {
         ItemStackKey replacement = ItemStackReplacementManager.getItemReplacement(item, metadata);
 
@@ -34,13 +36,14 @@ public abstract class MixinItemStack {
     }
 
     @Inject(method = "readFromNBT(Lnet/minecraft/nbt/NBTTagCompound;)V", at = @At("RETURN"))
+    @SuppressWarnings("unused")
     private void onReadFromNBTReturn(NBTTagCompound p_77963_1_, CallbackInfo ci) {
         ItemStackKey replacement = ItemStackReplacementManager.getItemReplacement(field_151002_e, itemDamage);
 
         if (replacement == null) return;
 
-        func_150996_a(replacement.getItem());
         itemDamage = replacement.getDamage();
+        func_150996_a(replacement.getItem());
     }
 
     @Unique

src/main/java/com/colen/postea/mixins/early/MixinTileEntity.java

@@ -0,0 +1,80 @@
+package com.colen.postea.mixins.early;
+
+import com.colen.postea.API.TileEntityReplacementManager;
+import com.colen.postea.API.TileTransformer;
+import cpw.mods.fml.common.FMLLog;
+import net.minecraft.nbt.NBTTagCompound;
+import net.minecraft.tileentity.TileEntity;
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.Logger;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Overwrite;
+import org.spongepowered.asm.mixin.Shadow;
+
+import java.util.Map;
+
+@Mixin(TileEntity.class)
+@SuppressWarnings("unused")
+public class MixinTileEntity {
+
+    @Shadow
+    private static Logger logger;
+
+    @Shadow
+    private static Map nameToClassMap;
+
+    /**
+     * Creates a new entity and loads its data from the specified NBT.
+     */
+    @Overwrite
+    @SuppressWarnings("unused")
+    public static TileEntity createAndLoadEntity(NBTTagCompound nbt) {
+        TileEntity tileentity = null;
+
+        Class oclass = null;
+        try
+        {
+            String tileEntityStringName = nbt.getString("id");
+            TileTransformer tileTransformer = TileEntityReplacementManager.getTileReplacementTransformer(tileEntityStringName);
+
+
+            if (tileTransformer == null) {
+                oclass = (Class)nameToClassMap.get(tileEntityStringName);
+            } else {
+                oclass = tileTransformer.getTileClass();
+                tileTransformer.modifyNBT(nbt);
+            }
+
+            if (oclass != null)
+            {
+                tileentity = (TileEntity)oclass.newInstance();
+            }
+        }
+        catch (Exception exception)
+        {
+            exception.printStackTrace();
+        }
+
+        if (tileentity != null)
+        {
+            try
+            {
+                tileentity.readFromNBT(nbt);
+            }
+            catch (Exception ex)
+            {
+                FMLLog.log(Level.ERROR, ex,
+                    "A TileEntity %s(%s) has thrown an exception during loading, its state cannot be restored. Report this to the mod author",
+                    nbt.getString("id"), oclass.getName());
+                tileentity = null;
+            }
+        }
+        else
+        {
+            logger.warn("Skipping BlockEntity with id " + nbt.getString("id"));
+        }
+
+        return tileentity;
+    }
+
+}