diff --git a/nomos-core/src/block.rs b/nomos-core/src/block.rs
index 065bc39e..7514707d 100644
--- a/nomos-core/src/block.rs
+++ b/nomos-core/src/block.rs
@@ -10,25 +10,29 @@ pub type TxHash = [u8; 32];
 
 /// A block
 #[derive(Clone, Debug, Serialize, Deserialize)]
-pub struct Block<TxId: Clone + Eq + Hash> {
-    header: BlockHeader,
+pub struct Block<Qc: Clone, TxId: Clone + Eq + Hash> {
+    header: BlockHeader<Qc>,
     transactions: IndexSet<TxId>,
 }
 
 /// A block header
 #[derive(Copy, Clone, Default, Debug, Serialize, Deserialize)]
-pub struct BlockHeader {
+pub struct BlockHeader<Qc: Clone> {
     id: BlockId,
+    qc: Qc,
 }
 
 /// Identifier of a block
 pub type BlockId = [u8; 32];
 
-impl<TxId: Clone + Eq + Hash> Block<TxId> {
-    pub fn new(header: BlockHeader, txs: impl Iterator<Item = TxId>) -> Self {
+impl<Qc: Clone, TxId: Clone + Eq + Hash> Block<Qc, TxId> {
+    pub fn new(qc: Qc, txs: impl Iterator<Item = TxId>) -> Self {
+        let transactions = txs.collect();
+        // FIXME: Calculate header Id
+        let header = BlockHeader { id: [0; 32], qc };
         Self {
             header,
-            transactions: txs.collect(),
+            transactions,
         }
     }
 
@@ -37,8 +41,8 @@ impl<TxId: Clone + Eq + Hash> Block<TxId> {
         Bytes::new()
     }
 
-    pub fn header(&self) -> BlockHeader {
-        self.header
+    pub fn header(&self) -> BlockHeader<Qc> {
+        self.header.clone()
     }
 
     pub fn transactions(&self) -> impl Iterator<Item = &TxId> + '_ {
@@ -46,8 +50,12 @@ impl<TxId: Clone + Eq + Hash> Block<TxId> {
     }
 }
 
-impl BlockHeader {
+impl<Qc: Clone> BlockHeader<Qc> {
     pub fn id(&self) -> BlockId {
         self.id
     }
+
+    pub fn qc(&self) -> &Qc {
+        &self.qc
+    }
 }
diff --git a/nomos-core/src/vote/carnot.rs b/nomos-core/src/vote/carnot.rs
index cebe8d6f..be4a336d 100644
--- a/nomos-core/src/vote/carnot.rs
+++ b/nomos-core/src/vote/carnot.rs
@@ -71,7 +71,8 @@ pub struct CarnotTally {
 #[async_trait::async_trait]
 impl Tally for CarnotTally {
     type Vote = Vote;
-    type Outcome = QuorumCertificate;
+    type Qc = QuorumCertificate;
+    type Outcome = ();
     type TallyError = CarnotTallyError;
     type Settings = CarnotTallySettings;
 
@@ -83,7 +84,7 @@ impl Tally for CarnotTally {
         &self,
         view: u64,
         mut vote_stream: S,
-    ) -> Result<Self::Outcome, Self::TallyError> {
+    ) -> Result<(Self::Qc, Self::Outcome), Self::TallyError> {
         let mut approved = 0usize;
         let mut seen = HashSet::new();
         while let Some(vote) = vote_stream.next().await {
@@ -106,10 +107,13 @@ impl Tally for CarnotTally {
             seen.insert(vote.voter);
             approved += 1;
             if approved >= self.settings.threshold {
-                return Ok(QuorumCertificate::Simple(SimpleQuorumCertificate {
-                    view,
-                    block: vote.block,
-                }));
+                return Ok((
+                    QuorumCertificate::Simple(SimpleQuorumCertificate {
+                        view,
+                        block: vote.block,
+                    }),
+                    (),
+                ));
             }
         }
         Err(CarnotTallyError::InsufficientVotes)
diff --git a/nomos-core/src/vote/mock.rs b/nomos-core/src/vote/mock.rs
index 3491edf9..68d1c328 100644
--- a/nomos-core/src/vote/mock.rs
+++ b/nomos-core/src/vote/mock.rs
@@ -46,7 +46,8 @@ impl MockQc {
 #[async_trait::async_trait]
 impl Tally for MockTally {
     type Vote = MockVote;
-    type Outcome = MockQc;
+    type Qc = MockQc;
+    type Outcome = ();
     type TallyError = Error;
     type Settings = MockTallySettings;
 
@@ -59,7 +60,7 @@ impl Tally for MockTally {
         &self,
         view: u64,
         mut vote_stream: S,
-    ) -> Result<Self::Outcome, Self::TallyError> {
+    ) -> Result<(Self::Qc, Self::Outcome), Self::TallyError> {
         let mut count_votes = 0;
         while let Some(vote) = vote_stream.next().await {
             if vote.view() != view {
@@ -67,7 +68,7 @@ impl Tally for MockTally {
             }
             count_votes += 1;
             if count_votes > self.threshold {
-                return Ok(MockQc { count_votes });
+                return Ok((MockQc { count_votes }, ()));
             }
         }
         Err(Error("Not enough votes".into()))
diff --git a/nomos-core/src/vote/mod.rs b/nomos-core/src/vote/mod.rs
index a8190e18..cb0e2b58 100644
--- a/nomos-core/src/vote/mod.rs
+++ b/nomos-core/src/vote/mod.rs
@@ -6,6 +6,7 @@ use futures::Stream;
 #[async_trait::async_trait]
 pub trait Tally {
     type Vote;
+    type Qc;
     type Outcome;
     type TallyError;
     type Settings: Clone;
@@ -14,5 +15,5 @@ pub trait Tally {
         &self,
         view: u64,
         vote_stream: S,
-    ) -> Result<Self::Outcome, Self::TallyError>;
+    ) -> Result<(Self::Qc, Self::Outcome), Self::TallyError>;
 }
diff --git a/nomos-services/consensus/src/leadership.rs b/nomos-services/consensus/src/leadership.rs
index 5a8f0dcf..b64e0bad 100644
--- a/nomos-services/consensus/src/leadership.rs
+++ b/nomos-services/consensus/src/leadership.rs
@@ -2,8 +2,8 @@
 use std::marker::PhantomData;
 // crates
 // internal
+use nomos_core::crypto::PrivateKey;
 use nomos_core::tx::Transaction;
-use nomos_core::{block::BlockHeader, crypto::PrivateKey};
 use nomos_mempool::MempoolMsg;
 
 use super::*;
@@ -18,9 +18,9 @@ pub struct Leadership<Tx: Transaction> {
     mempool: OutboundRelay<MempoolMsg<Tx>>,
 }
 
-pub enum LeadershipResult<'view, TxId: Clone + Eq + core::hash::Hash> {
+pub enum LeadershipResult<'view, Qc: Clone, TxId: Clone + Eq + core::hash::Hash> {
     Leader {
-        block: Block<TxId>,
+        block: Block<Qc, TxId>,
         _view: PhantomData<&'view u8>,
     },
     NotLeader {
@@ -41,12 +41,12 @@ where
     }
 
     #[allow(unused, clippy::diverging_sub_expression)]
-    pub async fn try_propose_block<'view, Qc>(
+    pub async fn try_propose_block<'view, Qc: Clone>(
         &self,
         view: &'view View,
         tip: &Tip,
         qc: Qc,
-    ) -> LeadershipResult<'view, Tx::Hash> {
+    ) -> LeadershipResult<'view, Qc, Tx::Hash> {
         // TODO: get the correct ancestor for the tip
         // let ancestor_hint = todo!("get the ancestor from the tip");
         let ancestor_hint = [0; 32];
@@ -60,10 +60,7 @@ where
 
             LeadershipResult::Leader {
                 _view: PhantomData,
-                block: Block::new(
-                    BlockHeader::default(),
-                    iter.map(|ref tx| <Tx as Transaction>::hash(tx)),
-                ),
+                block: Block::new(qc, iter.map(|ref tx| <Tx as Transaction>::hash(tx))),
             }
         } else {
             LeadershipResult::NotLeader { _view: PhantomData }
diff --git a/nomos-services/consensus/src/lib.rs b/nomos-services/consensus/src/lib.rs
index 5a7e173b..80eb1358 100644
--- a/nomos-services/consensus/src/lib.rs
+++ b/nomos-services/consensus/src/lib.rs
@@ -80,6 +80,7 @@ where
     M: MempoolAdapter<Tx = P::Tx>,
     P: MemPool,
     T: Tally,
+    T::Qc: Clone,
     O: Overlay<A, F, T, <P::Tx as Transaction>::Hash>,
     P::Tx: Transaction + Debug + 'static,
     <P::Tx as Transaction>::Hash: Debug,
@@ -101,6 +102,7 @@ where
     A: NetworkAdapter,
     P: MemPool,
     T: Tally,
+    T::Qc: Clone,
     P::Tx: Transaction + Debug,
     <P::Tx as Transaction>::Hash: Debug,
     M: MempoolAdapter<Tx = P::Tx>,
@@ -122,6 +124,7 @@ where
     T: Tally + Send + Sync + 'static,
     T::Settings: Send + Sync + 'static,
     T::Outcome: Send + Sync,
+    T::Qc: Clone + Send + Sync,
     P::Settings: Send + Sync + 'static,
     P::Tx: Debug + Clone + serde::de::DeserializeOwned + Send + Sync + 'static,
     <P::Tx as Transaction>::Hash: Debug + Send + Sync,
@@ -198,7 +201,7 @@ where
                     mempool_relay
                         .send(nomos_mempool::MempoolMsg::MarkInBlock {
                             ids: block.transactions().cloned().collect(),
-                            block: block.header(),
+                            block: block.header().id(),
                         })
                         .await
                         .map_err(|(e, _)| {
@@ -237,7 +240,7 @@ impl View {
         fountain: &F,
         tally: &T,
         leadership: &Leadership<Tx>,
-    ) -> Result<(Block<Tx::Hash>, View), Box<dyn std::error::Error + Send + Sync + 'static>>
+    ) -> Result<(Block<T::Qc, Tx::Hash>, View), Box<dyn std::error::Error + Send + Sync + 'static>>
     where
         A: NetworkAdapter + Send + Sync + 'static,
         F: FountainCode,
@@ -245,6 +248,7 @@ impl View {
         Tx::Hash: Debug,
         T: Tally + Send + Sync + 'static,
         T::Outcome: Send + Sync,
+        T::Qc: Clone,
         O: Overlay<A, F, T, Tx::Hash>,
     {
         let res = if self.is_leader(node_id) {
@@ -277,12 +281,13 @@ impl View {
         fountain: &F,
         tally: &T,
         leadership: &Leadership<Tx>,
-    ) -> Result<Block<<Tx as Transaction>::Hash>, ()>
+    ) -> Result<Block<T::Qc, <Tx as Transaction>::Hash>, ()>
     where
         A: NetworkAdapter + Send + Sync + 'static,
         F: FountainCode,
         T: Tally + Send + Sync + 'static,
         T::Outcome: Send + Sync,
+        T::Qc: Clone,
         Tx: Transaction,
         Tx::Hash: Debug,
         O: Overlay<A, F, T, Tx::Hash>,
@@ -309,11 +314,12 @@ impl View {
         adapter: &A,
         fountain: &F,
         tally: &T,
-    ) -> Result<(Block<Tx::Hash>, View), ()>
+    ) -> Result<(Block<T::Qc, Tx::Hash>, View), ()>
     where
         A: NetworkAdapter + Send + Sync + 'static,
         F: FountainCode,
         T: Tally + Send + Sync + 'static,
+        T::Qc: Clone,
         Tx: Transaction,
         Tx::Hash: Debug,
         O: Overlay<A, F, T, Tx::Hash>,
@@ -356,12 +362,15 @@ impl View {
     }
 
     // Verifies the block is new and the previous leader did not fail
-    fn pipelined_safe_block<TxId: Clone + Eq + Hash>(&self, _: &Block<TxId>) -> bool {
+    fn pipelined_safe_block<Qc: Clone, TxId: Clone + Eq + Hash>(
+        &self,
+        _: &Block<Qc, TxId>,
+    ) -> bool {
         // return b.view_n >= self.view_n && b.view_n == b.qc.view_n
         true
     }
 
-    fn generate_next_view<TxId: Clone + Eq + Hash>(&self, _b: &Block<TxId>) -> View {
+    fn generate_next_view<Qc: Clone, TxId: Clone + Eq + Hash>(&self, _b: &Block<Qc, TxId>) -> View {
         let mut seed = self.seed;
         seed[0] += 1;
         View {
diff --git a/nomos-services/consensus/src/overlay/committees.rs b/nomos-services/consensus/src/overlay/committees.rs
index 23f657c8..4c25b624 100644
--- a/nomos-services/consensus/src/overlay/committees.rs
+++ b/nomos-services/consensus/src/overlay/committees.rs
@@ -117,6 +117,7 @@ where
     Network: NetworkAdapter + Sync,
     Fountain: FountainCode + Sync,
     VoteTally: Tally + Sync,
+    VoteTally::Qc: serde::de::DeserializeOwned + Clone + Send + Sync + 'static,
     TxId: serde::de::DeserializeOwned + Clone + Hash + Eq + Send + Sync + 'static,
 {
     // we still need view here to help us initialize
@@ -130,13 +131,13 @@ where
         view: &View,
         adapter: &Network,
         fountain: &Fountain,
-    ) -> Result<Block<TxId>, FountainError> {
+    ) -> Result<Block<VoteTally::Qc, TxId>, FountainError> {
         assert_eq!(view.view_n, self.view_n, "view_n mismatch");
         let committee = self.committee;
         let message_stream = adapter.proposal_chunks_stream(committee, view).await;
         fountain.decode(message_stream).await.and_then(|b| {
             deserializer(&b)
-                .deserialize::<Block<TxId>>()
+                .deserialize::<Block<VoteTally::Qc, TxId>>()
                 .map_err(|e| FountainError::from(e.to_string().as_str()))
         })
     }
@@ -144,7 +145,7 @@ where
     async fn broadcast_block(
         &self,
         view: &View,
-        block: Block<TxId>,
+        block: Block<VoteTally::Qc, TxId>,
         adapter: &Network,
         fountain: &Fountain,
     ) {
@@ -173,7 +174,7 @@ where
     async fn approve_and_forward(
         &self,
         view: &View,
-        _block: &Block<TxId>,
+        _block: &Block<VoteTally::Qc, TxId>,
         _adapter: &Network,
         _tally: &VoteTally,
         _next_view: &View,
@@ -189,12 +190,7 @@ where
         todo!()
     }
 
-    async fn build_qc(
-        &self,
-        view: &View,
-        _adapter: &Network,
-        _tally: &VoteTally,
-    ) -> VoteTally::Outcome {
+    async fn build_qc(&self, view: &View, _adapter: &Network, _tally: &VoteTally) -> VoteTally::Qc {
         assert_eq!(view.view_n, self.view_n, "view_n mismatch");
         // maybe the leader publishing the QC?
         todo!()
diff --git a/nomos-services/consensus/src/overlay/flat.rs b/nomos-services/consensus/src/overlay/flat.rs
index 2b052a36..8e224ee5 100644
--- a/nomos-services/consensus/src/overlay/flat.rs
+++ b/nomos-services/consensus/src/overlay/flat.rs
@@ -18,36 +18,32 @@ const FLAT_COMMITTEE: Committee = Committee::root();
 /// As far as the API is concerned, this should be equivalent to any other
 /// overlay and far simpler to implement.
 /// For this reason, this might act as a 'reference' overlay for testing.
-pub struct Flat<TxId> {
+pub struct Flat {
     // TODO: this should be a const param, but we can't do that yet
     node_id: NodeId,
     view_n: u64,
-    _marker: std::marker::PhantomData<TxId>,
 }
 
-impl<TxId: Clone + Eq + Hash> Flat<TxId> {
+impl Flat {
     pub fn new(view_n: u64, node_id: NodeId) -> Self {
-        Self {
-            node_id,
-            view_n,
-            _marker: Default::default(),
-        }
+        Self { node_id, view_n }
     }
 
-    fn approve(&self, _block: &Block<TxId>) -> Approval {
+    fn approve<Qc: Clone, TxId: Clone + Eq + Hash>(&self, _block: &Block<Qc, TxId>) -> Approval {
         // we still need to define how votes look like
         Approval
     }
 }
 
 #[async_trait::async_trait]
-impl<Network, Fountain, VoteTally, TxId> Overlay<Network, Fountain, VoteTally, TxId> for Flat<TxId>
+impl<Network, Fountain, VoteTally, TxId> Overlay<Network, Fountain, VoteTally, TxId> for Flat
 where
     TxId: serde::de::DeserializeOwned + Clone + Eq + Hash + Send + Sync + 'static,
     Network: NetworkAdapter + Sync,
     Fountain: FountainCode + Sync,
     VoteTally: Tally + Sync,
     VoteTally::Vote: Serialize + DeserializeOwned + Send,
+    VoteTally::Qc: Clone + DeserializeOwned + Send + Sync + 'static,
 {
     fn new(view: &View, node: NodeId) -> Self {
         Flat::new(view.view_n, node)
@@ -58,12 +54,12 @@ where
         view: &View,
         adapter: &Network,
         fountain: &Fountain,
-    ) -> Result<Block<TxId>, FountainError> {
+    ) -> Result<Block<VoteTally::Qc, TxId>, FountainError> {
         assert_eq!(view.view_n, self.view_n, "view_n mismatch");
         let message_stream = adapter.proposal_chunks_stream(FLAT_COMMITTEE, view).await;
         fountain.decode(message_stream).await.and_then(|b| {
             deserializer(&b)
-                .deserialize::<Block<TxId>>()
+                .deserialize::<Block<VoteTally::Qc, TxId>>()
                 .map_err(|e| FountainError::from(e.to_string().as_str()))
         })
     }
@@ -71,7 +67,7 @@ where
     async fn broadcast_block(
         &self,
         view: &View,
-        block: Block<TxId>,
+        block: Block<VoteTally::Qc, TxId>,
         adapter: &Network,
         fountain: &Fountain,
     ) {
@@ -91,7 +87,7 @@ where
     async fn approve_and_forward(
         &self,
         view: &View,
-        block: &Block<TxId>,
+        block: &Block<VoteTally::Qc, TxId>,
         adapter: &Network,
         _tally: &VoteTally,
         _next_view: &View,
@@ -112,12 +108,7 @@ where
         Ok(())
     }
 
-    async fn build_qc(
-        &self,
-        view: &View,
-        adapter: &Network,
-        tally: &VoteTally,
-    ) -> VoteTally::Outcome {
+    async fn build_qc(&self, view: &View, adapter: &Network, tally: &VoteTally) -> VoteTally::Qc {
         assert_eq!(view.view_n, self.view_n, "view_n mismatch");
 
         // for now, let's pretend that consensus is reached as soon as the
@@ -126,7 +117,7 @@ where
 
         // Shadow the original binding so that it can't be directly accessed
         // ever again.
-        if let Ok(qc) = tally.tally(view.view_n, stream).await {
+        if let Ok((qc, _)) = tally.tally(view.view_n, stream).await {
             qc
         } else {
             unimplemented!("consensus not reached")
diff --git a/nomos-services/consensus/src/overlay/mod.rs b/nomos-services/consensus/src/overlay/mod.rs
index 90664d92..502ea4c5 100644
--- a/nomos-services/consensus/src/overlay/mod.rs
+++ b/nomos-services/consensus/src/overlay/mod.rs
@@ -20,7 +20,8 @@ pub trait Overlay<
     Fountain: FountainCode,
     VoteTally: Tally,
     TxId: Clone + Eq + Hash,
->
+> where
+    VoteTally::Qc: Clone,
 {
     fn new(view: &View, node: NodeId) -> Self;
 
@@ -29,11 +30,11 @@ pub trait Overlay<
         view: &View,
         adapter: &Network,
         fountain: &Fountain,
-    ) -> Result<Block<TxId>, FountainError>;
+    ) -> Result<Block<VoteTally::Qc, TxId>, FountainError>;
     async fn broadcast_block(
         &self,
         view: &View,
-        block: Block<TxId>,
+        block: Block<VoteTally::Qc, TxId>,
         adapter: &Network,
         fountain: &Fountain,
     );
@@ -43,7 +44,7 @@ pub trait Overlay<
     async fn approve_and_forward(
         &self,
         view: &View,
-        block: &Block<TxId>,
+        block: &Block<VoteTally::Qc, TxId>,
         adapter: &Network,
         vote_tally: &VoteTally,
         next_view: &View,
@@ -54,5 +55,5 @@ pub trait Overlay<
         view: &View,
         adapter: &Network,
         vote_tally: &VoteTally,
-    ) -> VoteTally::Outcome;
+    ) -> VoteTally::Qc;
 }
diff --git a/nomos-services/mempool/src/backend/mockpool.rs b/nomos-services/mempool/src/backend/mockpool.rs
index df86d089..274a1c97 100644
--- a/nomos-services/mempool/src/backend/mockpool.rs
+++ b/nomos-services/mempool/src/backend/mockpool.rs
@@ -6,7 +6,7 @@ use std::{collections::BTreeMap, time::UNIX_EPOCH};
 // crates
 // internal
 use crate::backend::{MemPool, MempoolError};
-use nomos_core::block::{BlockHeader, BlockId};
+use nomos_core::block::BlockId;
 use nomos_core::tx::Transaction;
 
 /// A mock mempool implementation that stores all transactions in memory in the order received.
@@ -73,16 +73,16 @@ where
         Box::new(pending_txs.into_iter())
     }
 
-    fn mark_in_block(&mut self, txs: &[<Self::Tx as Transaction>::Hash], block: BlockHeader) {
+    fn mark_in_block(&mut self, txs: &[<Self::Tx as Transaction>::Hash], block: BlockId) {
         let mut txs_in_block = Vec::with_capacity(txs.len());
         for tx_id in txs.iter() {
             if let Some(tx) = self.pending_txs.remove(tx_id) {
                 txs_in_block.push(tx);
             }
         }
-        let block_entry = self.in_block_txs.entry(block.id()).or_default();
+        let block_entry = self.in_block_txs.entry(block).or_default();
         self.in_block_txs_by_id
-            .extend(txs.iter().cloned().map(|tx| (tx, block.id())));
+            .extend(txs.iter().cloned().map(|tx| (tx, block)));
         block_entry.append(&mut txs_in_block);
     }
 
diff --git a/nomos-services/mempool/src/backend/mod.rs b/nomos-services/mempool/src/backend/mod.rs
index ffe7af65..39fa4a0d 100644
--- a/nomos-services/mempool/src/backend/mod.rs
+++ b/nomos-services/mempool/src/backend/mod.rs
@@ -1,7 +1,7 @@
 #[cfg(feature = "mock")]
 pub mod mockpool;
 
-use nomos_core::block::{BlockHeader, BlockId};
+use nomos_core::block::BlockId;
 use nomos_core::tx::Transaction;
 
 #[derive(thiserror::Error, Debug)]
@@ -30,7 +30,7 @@ pub trait MemPool {
     fn view(&self, ancestor_hint: BlockId) -> Box<dyn Iterator<Item = Self::Tx> + Send>;
 
     /// Record that a set of transactions were included in a block
-    fn mark_in_block(&mut self, txs: &[<Self::Tx as Transaction>::Hash], block: BlockHeader);
+    fn mark_in_block(&mut self, txs: &[<Self::Tx as Transaction>::Hash], block: BlockId);
 
     /// Returns all of the transactions for the block
     #[cfg(test)]
diff --git a/nomos-services/mempool/src/lib.rs b/nomos-services/mempool/src/lib.rs
index a5275d99..c1dc65c8 100644
--- a/nomos-services/mempool/src/lib.rs
+++ b/nomos-services/mempool/src/lib.rs
@@ -10,7 +10,7 @@ use tokio::sync::oneshot::Sender;
 // internal
 use crate::network::NetworkAdapter;
 use backend::MemPool;
-use nomos_core::block::{BlockHeader, BlockId};
+use nomos_core::block::BlockId;
 use nomos_core::tx::Transaction;
 use nomos_network::NetworkService;
 use overwatch_rs::services::{
@@ -57,7 +57,7 @@ pub enum MempoolMsg<Tx: Transaction> {
     },
     MarkInBlock {
         ids: Vec<Tx::Hash>,
-        block: BlockHeader,
+        block: BlockId,
     },
     Metrics {
         reply_channel: Sender<MempoolMetrics>,