diff --git a/types/block.go b/types/block.go
index 7d4551e5b..b13b3ac1d 100644
--- a/types/block.go
+++ b/types/block.go
@@ -17,7 +17,8 @@ const (
 	// MaxHeaderBytes is a maximum header size (including amino overhead).
 	MaxHeaderBytes = 478
 
-	// MaxAminoOverheadForBlock - amino overhead to encode the block.
+	// MaxAminoOverheadForBlock - maximum amino overhead to encode a block (up to
+	// MaxBlockSizeBytes in size).
 	MaxAminoOverheadForBlock = 4
 )
 
diff --git a/types/block_test.go b/types/block_test.go
index 3ca1da616..4c74439c1 100644
--- a/types/block_test.go
+++ b/types/block_test.go
@@ -107,7 +107,6 @@ func TestBlockMakePartSet(t *testing.T) {
 func TestBlockMakePartSetWithEvidence(t *testing.T) {
 	assert.Nil(t, (*Block)(nil).MakePartSet(2))
 
-	txs := []Tx{Tx("foo"), Tx("bar")}
 	lastID := makeBlockIDRandom()
 	h := int64(3)
 
@@ -118,7 +117,7 @@ func TestBlockMakePartSetWithEvidence(t *testing.T) {
 	ev := NewMockGoodEvidence(h, 0, valSet.Validators[0].Address)
 	evList := []Evidence{ev}
 
-	partSet := MakeBlock(h, txs, commit, evList).MakePartSet(1024)
+	partSet := MakeBlock(h, []Tx{Tx("Hello World")}, commit, evList).MakePartSet(1024)
 	assert.NotNil(t, partSet)
 	assert.Equal(t, 2, partSet.Total())
 }
diff --git a/types/tx.go b/types/tx.go
index 53fd79c5b..896d7be07 100644
--- a/types/tx.go
+++ b/types/tx.go
@@ -12,7 +12,8 @@ import (
 )
 
 const (
-	// MaxAminoOverheadForTx - amino overhead to encode a transaction.
+	// MaxAminoOverheadForTx - maximum amino overhead to encode a transaction
+	// (ranges from 1 to 4 bytes).
 	MaxAminoOverheadForTx = 4
 )