diff --git a/src/main.cpp b/src/main.cpp
index 4f156a6c04..92f747fbb7 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3751,6 +3751,15 @@ bool ContextualCheckBlock(const CBlock& block, CValidationState& state, CBlockIn
     //     }
     // }
 
+    // Size limits
+    unsigned int nMaxBlockSize = std::min(
+        (unsigned int)sporkManager.GetSporkValue(SPORK_105_MAX_BLOCK_SIZE), 
+        MAX_BLOCK_SIZE_CURRENT
+    );
+
+    if (::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION) > nMaxBlockSize)
+        return state.DoS(100, false, REJECT_INVALID, "bad-blk-length", false, "size limits failed");
+
     return true;
 }
 
diff --git a/src/miner.cpp b/src/miner.cpp
index 40fdecc29b..da9b38ec66 100644
--- a/src/miner.cpp
+++ b/src/miner.cpp
@@ -228,7 +228,12 @@ CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn, CWallet* pwallet,
     unsigned int nBlockMaxSize = GetArg("-blockmaxsize", DEFAULT_BLOCK_MAX_SIZE);
     // Limit to betweeen 1K and MAX_BLOCK_SIZE-1K for sanity:
     unsigned int nBlockMaxSizeNetwork = MAX_BLOCK_SIZE_CURRENT;
-    nBlockMaxSize = std::max((unsigned int)1000, std::min((nBlockMaxSizeNetwork - 1000), nBlockMaxSize));
+    nBlockMaxSize = std::max(
+        (unsigned int)1000, 
+        std::min(
+            (unsigned int)sporkManager.GetSporkValue(SPORK_105_MAX_BLOCK_SIZE), 
+            nBlockMaxSizeNetwork, 
+            nBlockMaxSize));
 
     // How much of the block should be dedicated to high-priority transactions,
     // included regardless of the fees they pay
diff --git a/src/policy/policy.h b/src/policy/policy.h
index f20381225d..872829751f 100644
--- a/src/policy/policy.h
+++ b/src/policy/policy.h
@@ -17,7 +17,7 @@ class CChainParams;
 class CCoinsViewCache;
 
 /** Default for -blockmaxsize and -blockminsize, which control the range of sizes the mining code will create **/
-static const unsigned int DEFAULT_BLOCK_MAX_SIZE = 750000;
+static const unsigned int DEFAULT_BLOCK_MAX_SIZE = MAX_BLOCK_SIZE_CURRENT;
 static const unsigned int DEFAULT_BLOCK_MIN_SIZE = 0;
 /** Default for -blockprioritysize, maximum space for zero/low-fee transactions **/
 static const unsigned int DEFAULT_BLOCK_PRIORITY_SIZE = 50000;
diff --git a/src/spork.cpp b/src/spork.cpp
index e2a22c9a46..6ed7166b26 100644
--- a/src/spork.cpp
+++ b/src/spork.cpp
@@ -30,7 +30,8 @@ std::vector<CSporkDef> sporkDefs = {
     MAKE_SPORK_DEF(SPORK_101_SERVICES_ENFORCEMENT,          4070908800ULL), // OFF
     MAKE_SPORK_DEF(SPORK_102_FORCE_ENABLED_MASTERNODE,      4070908800ULL), // OFF
     MAKE_SPORK_DEF(SPORK_103_PING_MESSAGE_SALT,             4070908800ULL), // OFF
-    MAKE_SPORK_DEF(SPORK_104_MAX_BLOCK_TIME,                    4070908800ULL), // OFF        
+    MAKE_SPORK_DEF(SPORK_104_MAX_BLOCK_TIME,                4070908800ULL), // OFF        
+    MAKE_SPORK_DEF(SPORK_105_MAX_BLOCK_SIZE,                4070908800ULL), // OFF   
 
 	// Unused dummy sporks.
 	//TODO: Needed to be removed in the future when the old nodes cut from the network.
diff --git a/src/sporkid.h b/src/sporkid.h
index 0ada9268b5..9d54abea0d 100644
--- a/src/sporkid.h
+++ b/src/sporkid.h
@@ -34,6 +34,7 @@ enum SporkId : int32_t {
     SPORK_102_FORCE_ENABLED_MASTERNODE          = 10101,
     SPORK_103_PING_MESSAGE_SALT                 = 10102,
     SPORK_104_MAX_BLOCK_TIME                    = 10103,
+    SPORK_105_MAX_BLOCK_SIZE                    = 10104,
 
 	// Unused dummy sporks.
 	//TODO needed to be removed in the future when the old nodes cut from the network.