diff --git a/src/main.h b/src/main.h
index 64b844db0..66808a57a 100644
--- a/src/main.h
+++ b/src/main.h
@@ -48,10 +48,10 @@ class CValidationState;
 struct CNodeStateStats;
 
 /** 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;
 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;
+static const unsigned int DEFAULT_BLOCK_PRIORITY_SIZE = DEFAULT_BLOCK_MAX_SIZE / 2;
 /** Default for accepting alerts from the P2P network. */
 static const bool DEFAULT_ALERTS = true;
 /** Minimum alert priority for enabling safe mode. */
@@ -93,6 +93,10 @@ static const unsigned int DATABASE_FLUSH_INTERVAL = 24 * 60 * 60;
 /** Maximum length of reject messages. */
 static const unsigned int MAX_REJECT_MESSAGE_LENGTH = 111;
 
+// Sanity check the magic numbers when we change them
+BOOST_STATIC_ASSERT(DEFAULT_BLOCK_MAX_SIZE <= MAX_BLOCK_SIZE);
+BOOST_STATIC_ASSERT(DEFAULT_BLOCK_PRIORITY_SIZE <= DEFAULT_BLOCK_MAX_SIZE);
+
 #define equihash_parameters_acceptable(N, K) \
     ((CBlockHeader::HEADER_SIZE + equihash_solution_size(N, K))*MAX_HEADERS_RESULTS < \
      MAX_PROTOCOL_MESSAGE_LENGTH-1000)