diff --git a/lib/bcoin/block.js b/lib/bcoin/block.js
index 95a91542..e62473b1 100644
--- a/lib/bcoin/block.js
+++ b/lib/bcoin/block.js
@@ -47,18 +47,14 @@ function Block(data) {
   bcoin.abstractblock.call(this, data);
 
   this.type = 'block';
-  this.txs = data.txs || [];
+  this.txs = [];
   this._cbHeight = null;
   this._commitmentHash = null;
   this._raw = null;
 
-  for (i = 0; i < this.txs.length; i++) {
-    tx = this.txs[i];
-
-    if (tx instanceof bcoin.tx)
-      continue;
-
-    this.txs[i] = new bcoin.tx(tx, this, i);
+  if (data.txs) {
+    for (i = 0; i < data.txs.length; i++)
+      this.addTX(data.txs[i]);
   }
 }
 
@@ -208,6 +204,26 @@ Block.prototype.hasWitness = function hasWitness() {
   return false;
 };
 
+/**
+ * Add a transaction to the block's tx vector.
+ * @param {TX|NakedTX} tx
+ * @returns {TX}
+ */
+
+Block.prototype.addTX = function addTX(tx) {
+  var index;
+
+  if (!(tx instanceof bcoin.tx))
+    tx = new bcoin.tx(tx);
+
+  index = this.txs.push(tx) - 1;
+
+  if (!this.mutable)
+    tx.setBlock(this, index);
+
+  return tx;
+};
+
 /**
  * Test the block's transaction vector against a hash.
  * @param {Hash|TX} hash
diff --git a/lib/bcoin/merkleblock.js b/lib/bcoin/merkleblock.js
index 5da01172..47e16c12 100644
--- a/lib/bcoin/merkleblock.js
+++ b/lib/bcoin/merkleblock.js
@@ -92,6 +92,23 @@ MerkleBlock.prototype.getRaw = function getRaw() {
   return this._raw;
 };
 
+/**
+ * Add a transaction to the block's tx vector.
+ * @param {TX|NakedTX} tx
+ * @returns {TX}
+ */
+
+MerkleBlock.prototype.addTX = function addTX(tx) {
+  if (!(tx instanceof bcoin.tx))
+    tx = new bcoin.tx(tx);
+
+  this.txs.push(tx);
+
+  tx.setBlock(this, -1);
+
+  return tx;
+};
+
 /**
  * Test the block's _matched_ transaction vector against a hash.
  * @param {Hash|TX} hash
diff --git a/lib/bcoin/miner.js b/lib/bcoin/miner.js
index ec40b199..c5dc7ed6 100644
--- a/lib/bcoin/miner.js
+++ b/lib/bcoin/miner.js
@@ -407,7 +407,7 @@ function MinerBlock(options) {
     height: this.height
   });
 
-  this.block.txs.push(this.coinbase);
+  this.block.addTX(this.coinbase);
 
   if (options.witness) {
     // Set up the witness nonce and
@@ -489,7 +489,7 @@ MinerBlock.prototype.addTX = function addTX(tx) {
     return false;
 
   // Add the tx to our block
-  this.block.txs.push(tx);
+  this.block.addTX(tx);
 
   // Update coinbase value
   this.updateCoinbase();
diff --git a/lib/bcoin/peer.js b/lib/bcoin/peer.js
index 96123ae9..683470af 100644
--- a/lib/bcoin/peer.js
+++ b/lib/bcoin/peer.js
@@ -581,18 +581,18 @@ Peer.prototype._onPacket = function onPacket(packet) {
     case 'filterclear':
       return this._handleFilterClear(payload);
     case 'block':
-      payload = bcoin.compactblock(payload);
+      payload = new bcoin.compactblock(payload);
       this._emit(cmd, payload);
       break;
     case 'merkleblock':
-      payload = bcoin.merkleblock(payload);
+      payload = new bcoin.merkleblock(payload);
       this.lastBlock = payload;
       break;
     case 'tx':
-      payload = bcoin.tx(payload, this.lastBlock);
+      payload = new bcoin.tx(payload);
       if (this.lastBlock) {
-        if (payload.block) {
-          this.lastBlock.txs.push(payload);
+        if (this.lastBlock.hasTX(payload)) {
+          this.lastBlock.addTX(payload);
           break;
         }
         this._emitMerkle();
diff --git a/lib/bcoin/tx.js b/lib/bcoin/tx.js
index a04505c0..b1a66310 100644
--- a/lib/bcoin/tx.js
+++ b/lib/bcoin/tx.js
@@ -20,9 +20,6 @@ var BufferWriter = require('./writer');
  * @exports TX
  * @constructor
  * @param {NakedTX} data - Transaction fields.
- * @param {(Block|MerkleBlock)?} block - Block the transaction was included in.
- * @param {Number?} index - The index of the transaction in the block's
- * transaction vector.
  * @property {String} type - "tx" (inv type).
  * @property {Number} version - Transaction version. Note that BCoin reads
  * versions as unsigned even though they are signed at the protocol level.
@@ -51,11 +48,11 @@ var BufferWriter = require('./writer');
  * witness is present. All zeroes if coinbase).
  */
 
-function TX(data, block, index) {
+function TX(data) {
   var i;
 
   if (!(this instanceof TX))
-    return new TX(data, block, index);
+    return new TX(data);
 
   assert(data, 'TX data is required.');
   assert(typeof data.version === 'number');
@@ -92,15 +89,6 @@ function TX(data, block, index) {
 
   for (i = 0; i < data.outputs.length; i++)
     this.outputs.push(new bcoin.output(data.outputs[i]));
-
-  if (block && this.ts === 0) {
-    if (block.type === 'merkleblock') {
-      if (block.hasTX(this))
-        this.setBlock(block, index);
-    } else {
-      this.setBlock(block, index);
-    }
-  }
 }
 
 /**
@@ -164,7 +152,7 @@ TX.prototype.setBlock = function setBlock(block, index) {
   this.ts = block.ts;
   this.block = block.hash('hex');
   this.height = block.height;
-  this.index = index;
+  this.index = index == null ? -1 : index;
   this.ps = 0;
 };