diff --git a/spec/src/consensus.rs b/spec/src/consensus.rs
index 8a2c968eaa..6ff74b690d 100644
--- a/spec/src/consensus.rs
+++ b/spec/src/consensus.rs
@@ -22,13 +22,14 @@ pub(crate) const MEDIAN_TIME_BLOCK_COUNT: usize = 11;
 pub(crate) const ORPHAN_RATE_TARGET_RECIP: u64 = 20;
 
 const MAX_BLOCK_INTERVAL: u64 = 60 * 1000; // 60s
-const MIN_BLOCK_INTERVAL: u64 = 5 * 1000; // 5s
+const MIN_BLOCK_INTERVAL: u64 = 8 * 1000; // 8s
+const TWO_IN_TWO_OUT_CYCLES: Cycle = 2_580_000;
 pub(crate) const EPOCH_DURATION_TARGET: u64 = 8 * 60 * 60 * 1000; // 8 hours
-pub(crate) const MAX_EPOCH_LENGTH: u64 = EPOCH_DURATION_TARGET / MIN_BLOCK_INTERVAL; // 2880
-pub(crate) const MIN_EPOCH_LENGTH: u64 = EPOCH_DURATION_TARGET / MAX_BLOCK_INTERVAL; // 240
+pub(crate) const MAX_EPOCH_LENGTH: u64 = EPOCH_DURATION_TARGET / MIN_BLOCK_INTERVAL; // 3600
+pub(crate) const MIN_EPOCH_LENGTH: u64 = EPOCH_DURATION_TARGET / MAX_BLOCK_INTERVAL; // 480
 pub(crate) const GENESIS_EPOCH_LENGTH: u64 = 2_000;
 pub(crate) const MAX_BLOCK_BYTES: u64 = 2_000_000; // 2mb
-pub(crate) const MAX_BLOCK_CYCLES: u64 = 10_000_000_000;
+pub(crate) const MAX_BLOCK_CYCLES: u64 = TWO_IN_TWO_OUT_CYCLES * 200 * 8;
 pub(crate) const MAX_BLOCK_PROPOSALS_LIMIT: u64 = 3_000;
 pub(crate) const BLOCK_VERSION: u32 = 0;