diff --git a/packages/SwingSet/src/controller.js b/packages/SwingSet/src/controller.js
index 5be5f7c9625..2b16c852610 100644
--- a/packages/SwingSet/src/controller.js
+++ b/packages/SwingSet/src/controller.js
@@ -27,7 +27,9 @@ import { insistCapData } from './capdata';
 import { parseVatSlot } from './parseVatSlots';
 
 // FIXME: Put this somewhere better.
-process.on('unhandledRejection', e => console.log('unhandledRejection', e));
+process.on('unhandledRejection', e =>
+  console.log('UnhandledPromiseRejectionWarning:', e),
+);
 
 const ADMIN_DEVICE_PATH = require.resolve('./kernel/vatAdmin/vatAdmin-src');
 const ADMIN_VAT_PATH = require.resolve('./kernel/vatAdmin/vatAdminWrapper');
diff --git a/packages/cosmic-swingset/Makefile b/packages/cosmic-swingset/Makefile
index 138af4babdd..5701e1386dd 100644
--- a/packages/cosmic-swingset/Makefile
+++ b/packages/cosmic-swingset/Makefile
@@ -3,8 +3,8 @@ CHAIN_ID = agoric
 INITIAL_TOKENS = 1000agmedallion
 
 # By default, make the fake chain in scenario3 produce
-# "blocks" at 5-second intervals.
-FAKE_CHAIN_DELAY = 5
+# "blocks" as soon as they come in.
+FAKE_CHAIN_DELAY = 0
 
 NUM_SOLOS?=1
 BASE_PORT?=8000
@@ -102,13 +102,14 @@ scenario2-run-client:
 scenario3-setup:
 	rm -rf t3
 	bin/ag-solo init t3 --egresses=fake
-	(cd t3 && \
-			../bin/ag-solo set-fake-chain --role=two_chain --delay=$(FAKE_CHAIN_DELAY) myFakeGCI)
 	@echo 'Execute `make scenario3-run` to run the client and simulated chain'
 
 # This runs both the client and the fake chain.
 scenario3-run-client: scenario3-run
+# Set the fake chain here in case the delay has changed.
 scenario3-run:
+	(cd t3 && \
+			../bin/ag-solo set-fake-chain --role=two_chain --delay=$(FAKE_CHAIN_DELAY) myFakeGCI)
 	cd t3 && ../bin/ag-solo start --role=two_client
 
 # These rules are the old scenario3.  No fake delay at all.
diff --git a/packages/cosmic-swingset/lib/ag-solo/fake-chain.js b/packages/cosmic-swingset/lib/ag-solo/fake-chain.js
index 9df16309d73..efc7ea21a98 100644
--- a/packages/cosmic-swingset/lib/ag-solo/fake-chain.js
+++ b/packages/cosmic-swingset/lib/ag-solo/fake-chain.js
@@ -51,16 +51,10 @@ export async function connectToFakeChain(basedir, GCI, role, delay, inbound) {
     try {
       const commitStamp = pretendLast + PRETEND_BLOCK_DELAY * 1000;
       const blockTime = Math.floor(commitStamp / 1000);
-      await deliverStartBlock(blockHeight, blockTime);
+      await deliverStartBlock(blockHeight, blockTime, true);
       for (let i = 0; i < thisBlock.length; i += 1) {
         const [newMessages, acknum] = thisBlock[i];
-        await deliverInbound(
-          bootAddress,
-          newMessages,
-          acknum,
-          blockHeight,
-          blockTime,
-        );
+        await deliverInbound(bootAddress, newMessages, acknum, true);
       }
 
       // Done processing, "commit the block".
diff --git a/packages/cosmic-swingset/lib/ag-solo/html/main.js b/packages/cosmic-swingset/lib/ag-solo/html/main.js
index 3844036a4c1..a9602c66eec 100644
--- a/packages/cosmic-swingset/lib/ag-solo/html/main.js
+++ b/packages/cosmic-swingset/lib/ag-solo/html/main.js
@@ -125,6 +125,14 @@ function run() {
         console.error(`error resetting`, e);
       }
     }
+    call({ type: 'getHighestHistory' })
+      .then(res => {
+        // eslint-disable-next-line no-use-before-define
+        setNextHistNum(res.highestHistory + 1);
+        // console.log(`nextHistNum is now ${nextHistNum}`, res);
+      })
+      .then(_ => call({ type: 'rebroadcastHistory' }))
+      .catch(_ => ws.close());
   });
 
   const inp = document.getElementById('input');
diff --git a/packages/cosmic-swingset/lib/ag-solo/start.js b/packages/cosmic-swingset/lib/ag-solo/start.js
index a2ab3d8f67e..c3941b6de6d 100644
--- a/packages/cosmic-swingset/lib/ag-solo/start.js
+++ b/packages/cosmic-swingset/lib/ag-solo/start.js
@@ -117,8 +117,8 @@ async function buildSwingset(
 
   async function processKernel() {
     await controller.run();
-    await saveState();
     if (swingSetRunning) {
+      await saveState();
       deliverOutbound();
     }
   }
@@ -128,7 +128,7 @@ async function buildSwingset(
       throw new Error(`inbound given non-Array: ${messages}`);
     }
     // console.log(`deliverInboundToMbx`, messages, ack);
-    if (mb.deliverInbound(sender, messages, ack)) {
+    if (mb.deliverInbound(sender, messages, ack, true)) {
       await processKernel();
     }
   }