diff --git a/.github/scripts/bench-reth-run.sh b/.github/scripts/bench-reth-run.sh
index 8a1d5b50d8..65b82a1dff 100755
--- a/.github/scripts/bench-reth-run.sh
+++ b/.github/scripts/bench-reth-run.sh
@@ -6,6 +6,7 @@
 # Usage: bench-reth-run.sh <label> <binary> <output-dir>
 #
 # Required env: SCHELK_MOUNT, BENCH_RPC_URL, BENCH_BLOCKS, BENCH_WARMUP_BLOCKS
+# Optional env: BENCH_BIG_BLOCKS (true/false), BENCH_WORK_DIR (for big blocks path)
 set -euo pipefail
 
 LABEL="$1"
@@ -73,6 +74,8 @@ if [ "${BENCH_CORES:-0}" -gt 0 ] && [ "$BENCH_CORES" -lt "$MAX_RETH" ]; then
 fi
 RETH_CPUS="1-${MAX_RETH}"
 
+BIG_BLOCKS="${BENCH_BIG_BLOCKS:-false}"
+
 RETH_ARGS=(
   node
   --datadir "$DATADIR"
@@ -87,6 +90,11 @@ RETH_ARGS=(
   --no-persist-peers
 )
 
+# Big blocks mode requires the testing API and skip-invalid-transactions
+if [ "$BIG_BLOCKS" = "true" ]; then
+  RETH_ARGS+=(--http.api eth,net,web3,reth,testing --testing.skip-invalid-transactions)
+fi
+
 if [ "${BENCH_SAMPLY:-false}" = "true" ]; then
   RETH_ARGS+=(--log.samply)
   SAMPLY="$(which samply)"
@@ -124,21 +132,35 @@ done
 # files are not root-owned (avoids EACCES on next checkout).
 BENCH_NICE="sudo nice -n -20 sudo -u $(id -un)"
 
-# Warmup
-$BENCH_NICE "$RETH_BENCH" new-payload-fcu \
-  --rpc-url "$BENCH_RPC_URL" \
-  --engine-rpc-url http://127.0.0.1:8551 \
-  --jwt-secret "$DATADIR/jwt.hex" \
-  --advance "${BENCH_WARMUP_BLOCKS:-50}" \
-  --reth-new-payload 2>&1 | sed -u "s/^/[bench] /"
+if [ "$BIG_BLOCKS" = "true" ]; then
+  # Big blocks mode: replay pre-generated payloads with gas ramp
+  BIG_BLOCKS_DIR="${BENCH_WORK_DIR}/big-blocks"
+  echo "Running big blocks benchmark (replay-payloads)..."
+  $BENCH_NICE "$RETH_BENCH" replay-payloads \
+    --reth-new-payload \
+    --gas-ramp-dir "$BIG_BLOCKS_DIR/gas-ramp-dir" \
+    --payload-dir "$BIG_BLOCKS_DIR/payloads" \
+    --engine-rpc-url http://127.0.0.1:8551 \
+    --jwt-secret "$DATADIR/jwt.hex" \
+    --output "$OUTPUT_DIR" 2>&1 | sed -u "s/^/[bench] /"
+else
+  # Standard mode: warmup + new-payload-fcu
+  # Warmup
+  $BENCH_NICE "$RETH_BENCH" new-payload-fcu \
+    --rpc-url "$BENCH_RPC_URL" \
+    --engine-rpc-url http://127.0.0.1:8551 \
+    --jwt-secret "$DATADIR/jwt.hex" \
+    --advance "${BENCH_WARMUP_BLOCKS:-50}" \
+    --reth-new-payload 2>&1 | sed -u "s/^/[bench] /"
 
-# Benchmark
-$BENCH_NICE "$RETH_BENCH" new-payload-fcu \
-  --rpc-url "$BENCH_RPC_URL" \
-  --engine-rpc-url http://127.0.0.1:8551 \
-  --jwt-secret "$DATADIR/jwt.hex" \
-  --advance "$BENCH_BLOCKS" \
-  --reth-new-payload \
-  --output "$OUTPUT_DIR" 2>&1 | sed -u "s/^/[bench] /"
+  # Benchmark
+  $BENCH_NICE "$RETH_BENCH" new-payload-fcu \
+    --rpc-url "$BENCH_RPC_URL" \
+    --engine-rpc-url http://127.0.0.1:8551 \
+    --jwt-secret "$DATADIR/jwt.hex" \
+    --advance "$BENCH_BLOCKS" \
+    --reth-new-payload \
+    --output "$OUTPUT_DIR" 2>&1 | sed -u "s/^/[bench] /"
+fi
 
 # cleanup runs via trap
diff --git a/.github/scripts/bench-reth-summary.py b/.github/scripts/bench-reth-summary.py
index 8eb8fbba39..8569879174 100755
--- a/.github/scripts/bench-reth-summary.py
+++ b/.github/scripts/bench-reth-summary.py
@@ -350,6 +350,7 @@ def generate_comparison_table(
     baseline_name: str,
     feature_name: str,
     feature_sha: str,
+    big_blocks: bool = False,
 ) -> str:
     """Generate a markdown comparison table between baseline and feature."""
     n = paired["blocks"]
@@ -390,7 +391,7 @@ def generate_comparison_table(
         f"| Mgas/s | {fmt_mgas(run1['mean_mgas_s'])} | {fmt_mgas(run2['mean_mgas_s'])} | {change_str(gas_pct, mgas_ci_pct, lower_is_better=False)} |",
         f"| Wall Clock | {fmt_s(run1['wall_clock_s'])} | {fmt_s(run2['wall_clock_s'])} | {change_str(wall_pct, wall_ci_pct, lower_is_better=True)} |",
         "",
-        f"*{n} blocks*",
+        f"*{n} {'big blocks' if big_blocks else 'blocks'}*",
     ]
     return "\n".join(lines)
 
@@ -466,6 +467,7 @@ def main():
     parser.add_argument("--feature-name", "--branch-name", default=None, help="Feature branch name")
     parser.add_argument("--feature-ref", "--branch-sha", "--feature-sha", default=None, help="Feature commit SHA")
     parser.add_argument("--behind-baseline", "--behind-main", type=int, default=0, help="Commits behind baseline")
+    parser.add_argument("--big-blocks", action="store_true", default=False, help="Big blocks mode")
     args = parser.parse_args()
 
     if len(args.baseline_csv) != len(args.feature_csv):
@@ -514,6 +516,7 @@ def main():
         baseline_name=baseline_name,
         feature_name=feature_name,
         feature_sha=feature_sha,
+        big_blocks=args.big_blocks,
     )
     print(f"Generated comparison ({paired_stats['n']} paired blocks, "
           f"mean diff {paired_stats['mean_diff_ms']:+.3f}ms ± {paired_stats['ci_ms']:.3f}ms)")
diff --git a/.github/workflows/bench.yml b/.github/workflows/bench.yml
index cdc44fbe96..f590785a49 100644
--- a/.github/workflows/bench.yml
+++ b/.github/workflows/bench.yml
@@ -12,7 +12,7 @@ on:
   workflow_dispatch:
     inputs:
       blocks:
-        description: "Number of blocks to benchmark"
+        description: "Number of blocks to benchmark (or 'big' for big blocks mode)"
         required: false
         default: "500"
         type: string
@@ -73,6 +73,7 @@ jobs:
       feature-name: ${{ steps.args.outputs.feature-name }}
       samply: ${{ steps.args.outputs.samply }}
       cores: ${{ steps.args.outputs.cores }}
+      big-blocks: ${{ steps.args.outputs.big-blocks }}
       comment-id: ${{ steps.ack.outputs.comment-id }}
     steps:
       - name: Check org membership
@@ -100,7 +101,7 @@ jobs:
         with:
           github-token: ${{ secrets.DEREK_PAT }}
           script: |
-            let pr, actor, blocks, warmup, baseline, feature, samply, cores;
+            let pr, actor, blocks, warmup, baseline, feature, samply, cores, bigBlocks;
 
             if (context.eventName === 'workflow_dispatch') {
               actor = '${{ github.actor }}';
@@ -110,6 +111,7 @@ jobs:
               feature = '${{ github.event.inputs.feature }}';
               samply = '${{ github.event.inputs.samply }}' === 'true' ? 'true' : 'false';
               cores = '${{ github.event.inputs.cores }}' || '0';
+              bigBlocks = blocks === 'big' ? 'true' : 'false';
 
               // Find PR for the selected branch
               const branch = '${{ github.ref_name }}';
@@ -129,7 +131,8 @@ jobs:
               actor = context.payload.comment.user.login;
 
               const body = context.payload.comment.body.trim();
-              const intArgs = new Set(['blocks', 'warmup', 'cores']);
+              const intArgs = new Set(['warmup', 'cores']);
+              const intOrKeywordArgs = new Map([['blocks', new Set(['big'])]]);
               const refArgs = new Set(['baseline', 'feature']);
               const boolArgs = new Set(['samply']);
               const defaults = { blocks: '500', warmup: '100', baseline: '', feature: '', samply: 'false', cores: '0' };
@@ -154,6 +157,15 @@ jobs:
                   } else {
                     defaults[key] = value;
                   }
+                } else if (intOrKeywordArgs.has(key)) {
+                  const keywords = intOrKeywordArgs.get(key);
+                  if (keywords.has(value)) {
+                    defaults[key] = value;
+                  } else if (/^\d+$/.test(value)) {
+                    defaults[key] = value;
+                  } else {
+                    invalid.push(`\`${key}=${value}\` (must be a positive integer or one of: ${[...keywords].join(', ')})`);
+                  }
                 } else if (refArgs.has(key)) {
                   if (!value) {
                     invalid.push(`\`${key}=\` (must be a git ref)`);
@@ -168,7 +180,7 @@ jobs:
               if (unknown.length) errors.push(`Unknown argument(s): \`${unknown.join('`, `')}\``);
               if (invalid.length) errors.push(`Invalid value(s): ${invalid.join(', ')}`);
               if (errors.length) {
-                const msg = `❌ **Invalid bench command**\n\n${errors.join('\n')}\n\n**Usage:** \`@decofe bench [blocks=N] [warmup=N] [baseline=REF] [feature=REF] [samply] [cores=N]\``;
+                const msg = `❌ **Invalid bench command**\n\n${errors.join('\n')}\n\n**Usage:** \`@decofe bench [blocks=N|big] [warmup=N] [baseline=REF] [feature=REF] [samply] [cores=N]\``;
                 await github.rest.issues.createComment({
                   owner: context.repo.owner,
                   repo: context.repo.repo,
@@ -184,6 +196,7 @@ jobs:
               feature = defaults.feature;
               samply = defaults.samply;
               cores = defaults.cores;
+              bigBlocks = blocks === 'big' ? 'true' : 'false';
             }
 
             // Resolve display names for baseline/feature
@@ -212,6 +225,7 @@ jobs:
             core.setOutput('feature-name', featureName);
             core.setOutput('samply', samply);
             core.setOutput('cores', cores);
+            core.setOutput('big-blocks', bigBlocks);
 
       - name: Acknowledge request
         id: ack
@@ -269,10 +283,12 @@ jobs:
             const baseline = '${{ steps.args.outputs.baseline-name }}';
             const feature = '${{ steps.args.outputs.feature-name }}';
             const samply = '${{ steps.args.outputs.samply }}' === 'true';
+            const bigBlocks = '${{ steps.args.outputs.big-blocks }}' === 'true';
             const samplyNote = samply ? ', samply: `enabled`' : '';
             const cores = '${{ steps.args.outputs.cores }}';
             const coresNote = cores && cores !== '0' ? `, cores: \`${cores}\`` : '';
-            const config = `**Config:** ${blocks} blocks, ${warmup} warmup blocks, baseline: \`${baseline}\`, feature: \`${feature}\`${samplyNote}${coresNote}`;
+            const blocksDesc = bigBlocks ? 'blocks: `big`' : `${blocks} blocks, ${warmup} warmup blocks`;
+            const config = `**Config:** ${blocksDesc}, baseline: \`${baseline}\`, feature: \`${feature}\`${samplyNote}${coresNote}`;
 
             const { data: comment } = await github.rest.issues.createComment({
               owner: context.repo.owner,
@@ -297,10 +313,12 @@ jobs:
             const baseline = '${{ steps.args.outputs.baseline-name }}';
             const feature = '${{ steps.args.outputs.feature-name }}';
             const samply = '${{ steps.args.outputs.samply }}' === 'true';
+            const bigBlocks = '${{ steps.args.outputs.big-blocks }}' === 'true';
             const samplyNote = samply ? ', samply: `enabled`' : '';
             const cores = '${{ steps.args.outputs.cores }}';
             const coresNote = cores && cores !== '0' ? `, cores: \`${cores}\`` : '';
-            const config = `**Config:** ${blocks} blocks, ${warmup} warmup blocks, baseline: \`${baseline}\`, feature: \`${feature}\`${samplyNote}${coresNote}`;
+            const blocksDesc = bigBlocks ? 'blocks: `big`' : `${blocks} blocks, ${warmup} warmup blocks`;
+            const config = `**Config:** ${blocksDesc}, baseline: \`${baseline}\`, feature: \`${feature}\`${samplyNote}${coresNote}`;
             const runUrl = `${context.serverUrl}/${context.repo.owner}/${context.repo.repo}/actions/runs/${context.runId}`;
 
             const numRunners = parseInt(process.env.BENCH_RUNNERS) || 1;
@@ -364,6 +382,7 @@ jobs:
       BENCH_WARMUP_BLOCKS: ${{ needs.reth-bench-ack.outputs.warmup }}
       BENCH_SAMPLY: ${{ needs.reth-bench-ack.outputs.samply }}
       BENCH_CORES: ${{ needs.reth-bench-ack.outputs.cores }}
+      BENCH_BIG_BLOCKS: ${{ needs.reth-bench-ack.outputs.big-blocks }}
       BENCH_COMMENT_ID: ${{ needs.reth-bench-ack.outputs.comment-id }}
     steps:
       - name: Clean up previous bench-work
@@ -383,13 +402,11 @@ jobs:
               repo: context.repo.repo,
               pull_number: parseInt(process.env.BENCH_PR),
             });
-            // For closed/merged PRs, the merge ref doesn't exist — use head SHA
-            if (pr.state !== 'open') {
-              core.info(`PR #${process.env.BENCH_PR} is ${pr.state}, using head SHA ${pr.head.sha}`);
-              core.setOutput('ref', pr.head.sha);
-            } else {
-              core.setOutput('ref', `refs/pull/${process.env.BENCH_PR}/merge`);
-            }
+            // Always use head SHA — the merge ref (refs/pull/N/merge) may not
+            // exist if the PR has conflicts, was force-pushed, or was
+            // merged/closed between this step and checkout.
+            core.info(`PR #${process.env.BENCH_PR} (${pr.state}), using head SHA ${pr.head.sha}`);
+            core.setOutput('ref', pr.head.sha);
 
       - uses: actions/checkout@v6
         with:
@@ -417,10 +434,12 @@ jobs:
             const baseline = '${{ needs.reth-bench-ack.outputs.baseline-name }}';
             const feature = '${{ needs.reth-bench-ack.outputs.feature-name }}';
             const samply = process.env.BENCH_SAMPLY === 'true';
+            const bigBlocks = process.env.BENCH_BIG_BLOCKS === 'true';
             const samplyNote = samply ? ', samply: `enabled`' : '';
             const cores = process.env.BENCH_CORES || '0';
             const coresNote = cores && cores !== '0' ? `, cores: \`${cores}\`` : '';
-            core.exportVariable('BENCH_CONFIG', `**Config:** ${blocks} blocks, ${warmup} warmup blocks, baseline: \`${baseline}\`, feature: \`${feature}\`${samplyNote}${coresNote}`);
+            const blocksDesc = bigBlocks ? 'blocks: `big`' : `${blocks} blocks, ${warmup} warmup blocks`;
+            core.exportVariable('BENCH_CONFIG', `**Config:** ${blocksDesc}, baseline: \`${baseline}\`, feature: \`${feature}\`${samplyNote}${coresNote}`);
 
             const { buildBody } = require('./.github/scripts/bench-update-status.js');
             await github.rest.issues.updateComment({
@@ -680,6 +699,25 @@ jobs:
           rm -rf "$BENCH_WORK_DIR"
           mkdir -p "$BENCH_WORK_DIR"
 
+      - name: Download big blocks
+        if: env.BENCH_BIG_BLOCKS == 'true'
+        run: |
+          set -euo pipefail
+          MC="mc --config-dir /home/ubuntu/.mc"
+          BUCKET="minio/reth-snapshots/reth-1-minimal-nightly-previous-big-blocks.tar.zst"
+          BIG_BLOCKS_DIR="${BENCH_WORK_DIR}/big-blocks"
+          rm -rf "$BIG_BLOCKS_DIR"; mkdir -p "$BIG_BLOCKS_DIR"
+          echo "Downloading big blocks from $BUCKET..."
+          $MC cat "$BUCKET" | pzstd -d -p 6 | tar -xf - -C "$BIG_BLOCKS_DIR"
+          echo "Big blocks downloaded to $BIG_BLOCKS_DIR"
+          # Verify expected directory structure
+          if [ ! -d "$BIG_BLOCKS_DIR/gas-ramp-dir" ] || [ ! -d "$BIG_BLOCKS_DIR/payloads" ]; then
+            echo "::error::Big blocks archive missing expected gas-ramp-dir/ or payloads/ directories"
+            ls -laR "$BIG_BLOCKS_DIR"
+            exit 1
+          fi
+          echo "Payload files: $(find "$BIG_BLOCKS_DIR/payloads" -name '*.json' | wc -l)"
+
       - name: Update status (running benchmarks)
         if: success() && env.BENCH_COMMENT_ID
         uses: actions/github-script@v8
@@ -813,6 +851,9 @@ jobs:
           if [ "$BEHIND_BASELINE" -gt 0 ]; then
             SUMMARY_ARGS="$SUMMARY_ARGS --behind-baseline $BEHIND_BASELINE"
           fi
+          if [ "${BENCH_BIG_BLOCKS:-false}" = "true" ]; then
+            SUMMARY_ARGS="$SUMMARY_ARGS --big-blocks"
+          fi
           # shellcheck disable=SC2086
           python3 .github/scripts/bench-reth-summary.py $SUMMARY_ARGS