Skip to product information
Usually ships in 2–4 business days.
Water Pump for GM Big Block 7.4 8.2 409 454 502 850454 18-3577 18-3574 9-42604
$215.59
Sale price
$215.59
Regular price
Available to Order
This Water Pump is a replacement water pump compatible with GM Big Block engines including 7.4L, 8.2L, 409, 454, 502 and matches OEM Part# 850454, 18-3577, 18-3574, 9-4264.
Need help finding the right part? Talk with a parts expert today.
Parts Support Hours: Monday–Friday, 8:00 AM–5:00 PM CT
Live Chat: Available 24/7
I needed a forklift part and wasn’t sure which one fit. They asked for the model and serial number, got back to me quickly, and made sure I ordered the right one. Really helpful.
Randy W. — Verified customer
Product Overview
This water pump is engineered for GM Big Block engines, covering displacements from 7.4L to 502. It circulates coolant efficiently to prevent overheating in high-performance vehicles, trucks, and marine applications. A direct replacement for part numbers 850454, 18-3577, 18-3574, and 9-4264, this heavy-duty pump restores original cooling system performance.
Key Features & Performance
- Direct fit for GM Big Block 7.4L, 8.2L, 409, 454, and 502 engines
- High-flow impeller design for superior coolant circulation
- Durable construction withstands high operating temperatures
- Includes gasket for straightforward installation
- Meets or exceeds OEM specifications for reliable performance
Fitment & Compatibility
- GM Big Block 7.4L (454)
- GM Big Block 8.2L (502)
- GM 409 V8
- GM 454 V8
- GM 502 V8
Common Uses
- Replacing worn or leaking water pumps on Chevrolet/GMC big block trucks and SUVs
- Cooling high-performance big block engines in hot rods and muscle cars
- Marine engine cooling in boats equipped with GM big block power
Technical Specifications
- Material: Cast iron housing with steel impeller
- Inlet/Outlet: Standard big block hose connections
- Part Number(s): 850454, 18-3577, 18-3574, 9-4264
Frequently Asked Questions
Q: Will this pump fit a 454 in a 1970 Chevelle? A: Yes, it is designed for 454 big block engines used in many classic Chevrolet vehicles, but verify pulley alignment and bracket fitment.
Q: Does it come with a gasket? A: Yes, a gasket is typically included for a complete installation. Always check the package contents upon receipt.
Product appearance and specifications may vary slightly by batch. Compatibility may vary by serial number. Verify fitment before purchase.