diff --git a/test/functional/feature_fee_estimation.py b/test/functional/feature_fee_estimation.py
index 8e97df2361..32a6bd5d59 100755
--- a/test/functional/feature_fee_estimation.py
+++ b/test/functional/feature_fee_estimation.py
@@ -133,12 +133,12 @@ class EstimateFeeTest(BitcoinTestFramework):
         which we will use to generate our transactions.
         """
         self.add_nodes(3, extra_args=[["-maxorphantx=1000", "-whitelist=127.0.0.1"],
-                                      ["-maxorphantx=1000"],
-                                      ["-maxorphantx=1000"]])
+                                      ["-blockmaxweight=68000", "-maxorphantx=1000"],
+                                      ["-blockmaxweight=32000", "-maxorphantx=1000"]])
         # Use node0 to mine blocks for input splitting
         # Node1 mines small blocks but that are bigger than the expected transaction rate.
-        # NOTE: the CreateNewBlock code starts counting block size at 1,000 bytes,
-        # (17k is room enough for 110 or so transactions)
+        # NOTE: the CreateNewBlock code starts counting block weight at 4,000 weight,
+        # (68k weight is room enough for 120 or so transactions)
         # Node2 is a stingy miner, that
         # produces too small blocks (room for only 55 or so transactions)
 
diff --git a/test/functional/feature_pruning.py b/test/functional/feature_pruning.py
index 227ae6cb36..3adde8dd73 100755
--- a/test/functional/feature_pruning.py
+++ b/test/functional/feature_pruning.py
@@ -124,7 +124,7 @@ class PruneTest(BitcoinTestFramework):
         # Reboot node 1 to clear its mempool (hopefully make the invalidate faster)
         # Lower the block max size so we don't keep mining all our big mempool transactions (from disconnected blocks)
         self.stop_node(1)
-        self.start_node(1, extra_args=["-maxreceivebuffer=20000","-checkblocks=5", "-disablesafemode"])
+        self.start_node(1, extra_args=["-maxreceivebuffer=20000","-blockmaxweight=20000", "-checkblocks=5", "-disablesafemode"])
 
         height = self.nodes[1].getblockcount()
         self.log.info("Current block height: %d" % height)
@@ -147,7 +147,7 @@ class PruneTest(BitcoinTestFramework):
 
         # Reboot node1 to clear those giant tx's from mempool
         self.stop_node(1)
-        self.start_node(1, extra_args=["-maxreceivebuffer=20000","-checkblocks=5", "-disablesafemode"])
+        self.start_node(1, extra_args=["-maxreceivebuffer=20000","-blockmaxweight=20000", "-checkblocks=5", "-disablesafemode"])
 
         self.log.info("Generating new longer chain of 300 more blocks")
         self.nodes[1].generate(300)