diff --git a/src/lib/components/Product.svelte b/src/lib/components/Product.svelte
index 0199b3c2..00ee5182 100644
--- a/src/lib/components/Product.svelte
+++ b/src/lib/components/Product.svelte
@@ -22,9 +22,14 @@
   export let priceOverride = null;
 
   export let VariantSelector = null;
+
+  // Per-variant timeline override carried by VariantSelector (e.g., harness
+  // JSON overrides like Tesla B's "4-8 weeks"). Treated as the authoritative
+  // backorder signal when present — shown regardless of Shopify stock state.
+  let variantBackordered = null;
   function handleVariantSelection(variant) {
     selectedVariantId = variant?.id || null;
-    backordered = variant?.currentlyNotInStock ? (variant.backordered || '1-12 weeks') : null;
+    variantBackordered = variant?.backordered || null;
   }
 
   let currentImageIndex = 0;
@@ -72,17 +77,23 @@
     }
   }
 
+  // Priority: static prop > per-variant JSON override (always shown) >
+  // Shopify-driven default ('1-12 weeks' when currentlyNotInStock).
+  $: effectiveBackordered = backordered
+    || variantBackordered
+    || (selectedVariant?.currentlyNotInStock ? '1-12 weeks' : null);
+
   let addToCartLabel;
   $: {
     if (disableBuyButtonText) {
       addToCartLabel = disableBuyButtonText;
     } else if (forceOutOfStock || (selectedVariant && !selectedVariant.availableForSale)) {
       addToCartLabel = "Out of stock";
-      if (backordered) {
-        addToCartLabel += ` (${backorderedPrefix}${backordered})`;
+      if (effectiveBackordered) {
+        addToCartLabel += ` (${backorderedPrefix}${effectiveBackordered})`;
       }
-    } else if (backordered) {
-      addToCartLabel = `Add to cart (${backorderedPrefix}${backordered})`;
+    } else if (effectiveBackordered) {
+      addToCartLabel = `Add to cart (${backorderedPrefix}${effectiveBackordered})`;
     } else {
       addToCartLabel = "Add to cart";
     }
diff --git a/src/lib/components/ProductDescriptions/CommaFour.svelte b/src/lib/components/ProductDescriptions/CommaFour.svelte
index a6293cf0..e727abb3 100644
--- a/src/lib/components/ProductDescriptions/CommaFour.svelte
+++ b/src/lib/components/ProductDescriptions/CommaFour.svelte
@@ -79,7 +79,7 @@
       backordered = null;
       disableBuyButtonText = null;
     } else if (value) {
-      backordered = value.currentlyNotInStock ? (value.backordered || '1-12 weeks') : null;
+      backordered = value.backordered || (value.currentlyNotInStock ? '1-12 weeks' : null);
       disableBuyButtonText = null;
     } else {
       backordered = null;
diff --git a/src/lib/data/products.js b/src/lib/data/products.js
index a6e91bae..a932796a 100644
--- a/src/lib/data/products.js
+++ b/src/lib/data/products.js
@@ -290,6 +290,7 @@ export const products = {
   "harness-connector": {
     title: "harness connector",
     id: "gid://shopify/Product/4310075310143",
+    inventoryFromProductId: "gid://shopify/Product/4447447908415", // shares physical inventory with car-harness; matched by variant title
     route: "/shop/harness-connector",
     category: "accessories",
     price: "$50",
diff --git a/src/routes/shop/[product]/+page.js b/src/routes/shop/[product]/+page.js
index 5e74c9c0..f9eb750b 100644
--- a/src/routes/shop/[product]/+page.js
+++ b/src/routes/shop/[product]/+page.js
@@ -39,11 +39,33 @@ export async function load({ url, params }) {
     }
   }
 
-  // Fetch from Shopify
-  const response = await getProduct(productInfo.id);
+  // Fetch from Shopify (in parallel with optional sibling for inventory overlay)
+  const [response, sourceResponse] = await Promise.all([
+    getProduct(productInfo.id),
+    productInfo.inventoryFromProductId ? getProduct(productInfo.inventoryFromProductId) : Promise.resolve(null),
+  ]);
   if (response.status === 200) {
     const product = response.body?.data?.product;
     if (product) {
+      // TODO: remove and use product bundles
+      // When this product shares physical stock with another Shopify product,
+      // overlay the sibling's inventory flags onto our variants by title match.
+      if (sourceResponse?.status === 200) {
+        const sourceVariants = sourceResponse.body?.data?.product?.variants?.nodes || [];
+        const sourceByTitle = new Map(sourceVariants.map(v => [v.title, v]));
+        product.variants = {
+          ...product.variants,
+          nodes: (product.variants?.nodes || []).map(v => {
+            const source = sourceByTitle.get(v.title);
+            if (!source) return v;
+            return {
+              ...v,
+              currentlyNotInStock: source.currentlyNotInStock,
+              availableForSale: source.availableForSale,
+            };
+          }),
+        };
+      }
       return {
         product: {
           ...product,