diff --git a/build/params.go b/build/params.go
index 480b90230..00808dbe4 100644
--- a/build/params.go
+++ b/build/params.go
@@ -48,6 +48,9 @@ const ForkLengthThreshold = 100
 // Blocks (e)
 const BlocksPerEpoch = 1
 
+// Blocks
+const Finality = 500
+
 // /////
 // Proofs
 
@@ -65,6 +68,9 @@ const PoStChallangeTime = ProvingPeriodDuration - 5
 // Blocks
 const PoStRandomnessLookback = 1
 
+// Blocks
+const SealRandomnessLookback = Finality
+
 // /////
 // Mining
 
diff --git a/node/modules/storageminer.go b/node/modules/storageminer.go
index ff51ca7b8..4f9df1c42 100644
--- a/node/modules/storageminer.go
+++ b/node/modules/storageminer.go
@@ -171,7 +171,7 @@ func SealTicketGen(api api.FullNode) sector.TicketFn {
 			return nil, xerrors.Errorf("getting head ts for SealTicket failed: %w", err)
 		}
 
-		r, err := api.ChainGetRandomness(ctx, ts, nil, build.RandomnessLookback)
+		r, err := api.ChainGetRandomness(ctx, ts, nil, build.SealRandomnessLookback)
 		if err != nil {
 			return nil, xerrors.Errorf("getting randomness for SealTicket failed: %w", err)
 		}
@@ -182,7 +182,7 @@ func SealTicketGen(api api.FullNode) sector.TicketFn {
 		}
 
 		return &sectorbuilder.SealTicket{
-			BlockHeight: ts.Height() - build.RandomnessLookback,
+			BlockHeight: ts.Height() - build.SealRandomnessLookback,
 			TicketBytes: tkt,
 		}, nil
 	}