# 863903A03 Mercruiser 863903A03 V8 Big Block 8.1L (496 MAG) Heat Exchanger Replacement

Mercruiser 863903A03 V8 Big Block 8.1L (496 MAG) Heat Exchanger Replacement

Replaces Mercruiser part no. 863903A03

Used on Mercruiser engine:

GM V8 Big Block 8.1L 496 MAG engines.

This heat exchanger has 3.5 inch diameter. For 4 inch diameter see 863903A01

This is a non OEM part MEC 863903A03

## Details

- **Price:** 2310.0 AUD
- **Vendor:** Mr Cool
- **Tags:** Sawley’s AAM Aftermarket – Cooling Systems Mr Cool | Marine Heat Exchangers & Kits

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 2310.00 AUD | In stock |

## Images

- 863903A03 Mercruiser 863903A03 V8 Big Block 8.1L (496 MAG) Heat Exchanger Replacement
- 863903A03 Mercruiser 863903A03 V8 Big Block 8.1L (496 MAG) Heat Exchanger Replacement

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/863903a03-mercruiser-863903a03-v8-big-block-8-1l-496-mag-heat-exchanger-replacement)
> Updated: 2026-06-23