---
product_id: 306399273
title: "GM Gen III & IV LS Billet Rear Passage Plug Oil Diverter Barbell"
brand: "improved racing"
price: "€ 39.26"
currency: EUR
in_stock: true
url: https://www.desertcart.ie/products/306399273-gm-gen-iii-and-iv-ls-billet-rear-passage-plug
store_origin: IE
region: Ireland
---

# CNC-machined billet aluminum Double O-ring leak-proof seal Proudly made in the USA GM Gen III & IV LS Billet Rear Passage Plug Oil Diverter Barbell

**Brand:** improved racing
**Price:** € 39.26
**Availability:** ✅ In Stock

## Summary

> ⚡ Upgrade your LS engine’s oil flow game — don’t let dirty oil slow you down!

## Quick Answers

- **What is this?** GM Gen III & IV LS Billet Rear Passage Plug Oil Diverter Barbell by improved racing
- **How much does it cost?** € 39.26 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.ie](https://www.desertcart.ie/products/306399273-gm-gen-iii-and-iv-ls-billet-rear-passage-plug)

## Best For

- improved racing enthusiasts

## Why This Product

- Trusted improved racing brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Easy Removal Design:** Threaded M4x0.7 hole allows quick, hassle-free installation and removal.
- • **American Craftsmanship:** Manufactured in the USA, guaranteeing top-tier quality and reliability.
- • **Direct OEM Replacement:** Seamlessly swaps with plastic OEM barbell plugs on GM LS Gen III & IV engines.
- • **Precision CNC Machining:** Engineered from billet 6061-T6 aluminum for unmatched durability and performance.
- • **Leak-Proof Double O-Ring Seal:** Ensures zero oil bypass, keeping your engine oil pristine and filtered.

## Overview

The Improved Racing GM Gen III & IV LS Billet Rear Passage Plug Oil Diverter Barbell is a precision CNC-machined billet aluminum replacement part designed to eliminate dirty oil bypass in GM LS Gen III & IV engines. Featuring a double O-ring seal for leak-proof performance and an easy removal threaded hole, this USA-made component ensures optimal oil filtration and engine longevity.

## Description

Improved Racing GM Gen III & IV LS Billet Rear Passage Plug Oil Diverter Barbell

## Features

- Improves oil flow and completely eliminates dirty engine oil from bypassing the filter
- Double O-ring design seal positively seals the oil gallery passage
- Direct replacement for plastic OEM barbell plug on GM LS Gen III & IV engines
- Precision CNC-machined from billet 6061-T6 aluminum with Viton O-rings
- Threaded M4x0.7 hole allows for easy removal from engine block
- Made in the USA.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| Manufacturer | Improved Racing |
| Brand | Improved Racing |
| Item Weight | 0.634 ounces |
| Package Dimensions | 4.57 x 3.74 x 0.47 inches |
| Item model number | EGM-501 |
| Manufacturer Part Number | EGM-501 |
| OEM Part Number | 12573460 |

## Product Details

- **Brand:** Improved Racing
- **Package Information:** Pouch
- **Vehicle Service Type:** Gen III and IV GM LS series engines
- **Automotive Fit Type:** Vehicle Specific Fit
- **Manufacturer:** Improved Racing

## Images

![GM Gen III & IV LS Billet Rear Passage Plug Oil Diverter Barbell - Image 1](https://m.media-amazon.com/images/I/41uS83nyh3L.jpg)

## Questions & Answers

**Q: do u need to replace the o-ring in the future?**
A: The O rings would only require replacement if it was removed after the initial installation. If you were removing during engine replacement or rebuilding, we would recommend replacement at that time.

**Q: Will this fit a 2008 gmc Savana 3500 6.0L?**
A: As long as it’s your standard LS block. Be at a 5.3, 5.7, 6.0, 6.2, or even a 7.0 Liter you are good to go. I bought this for my newly built 408 stroker 6 liter iron block and it is far superior to the stock style. I also like that it has a threaded portion in the back to be able to easily take it out if you ever need to, plus it’s double O-ringed.

**Q: Why is this one different than all the others? The barbell is longer on one end.**
A: Take a look at the last photo in the listing, where you can see the barbell installed in the engine. You can see it's designed so the tip fills the entire closed section of the passage. The barbell is only narrow where oil needs to flow around it. This helps create a better seal at the tip and also makes the barbell stronger.

**Q: 2008 chevy silverado 5.3 this will work on my engine**
A: Yes, this will fit all Gen III and IV LS and Vortec family blocks, so it will fit your 5.3

## Frequently Bought Together

- Improved Racing GM Gen III & IV LS Billet Rear Passage Plug Oil Diverter Barbell
- Dorman 635-518 Engine Rear Main Seal Cover Compatible with Select Models
- Camshaft Retainer Plate Gasket Compatible with LS Series Engines, &Bolt Kit ARP 134-1003 Gen III IV V for GM LS1 LS2 LS3 4.8 5.3L 6.0L 6.2L Vortec Corvette Cam

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**Shop now:** [https://www.desertcart.ie/products/306399273-gm-gen-iii-and-iv-ls-billet-rear-passage-plug](https://www.desertcart.ie/products/306399273-gm-gen-iii-and-iv-ls-billet-rear-passage-plug)

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*Product available on Desertcart Ireland*
*Store origin: IE*
*Last updated: 2026-03-07*