34 Review(s)

Water Restrictor Plate - Modified - 351C - New ~ 1970 - 1973 Mercury Cougar / 1970 - 1973 Ford Mustang

Item #: 53234

Cost: 2480

Earns: 124

Bonus: 0

Reproduction 351 Cleveland Water Restriction Plate for the 1970 1971 1972 and 1973 Mercury Cougar and Ford Mustang

Any 351 Cleveland

1970 Mercury Cougar
1971 Mercury Cougar
1972 Mercury Cougar
1973 Mercury Cougar
1970 Ford Mustang
1971 Ford Mustang
1972 Ford Mustang
1973 Ford Mustang

Quantity:

Price: $31.00

Options / Optional Addons

Item #	Description/Size	Availability	Qty Break	Price
14330	Thermostat Housing Gasket for the 351 Cleveland.	In-Stock Item	1	$3.16
41407	195° Thermostat for the Small Block in the 1967 - 1973 Mercury Cougar / Ford Mustang	In-Stock Item	1	$12.80 $7.68
41408	180° Thermostat for the Small Block in the 1967 - 1973 Mercury Cougar / Ford Mustang	In-Stock Item	1	$14.45 $8.67
41409	160° Thermostat for the Small Block in the 1967 - 1973 Mercury Cougar or Ford Mustang	In-Stock Item	1	$12.60 $7.56

Total:

$0.00

Update Price

In-Stock Item Quantity: 19

Availability

In-Stock Item - Ships in: Next Business Day

Applications

1970 Mercury Cougar, 1971 Mercury Cougar, 1972 Mercury Cougar, 1973 Mercury Cougar, 1970 Ford Mustang, 1971 Ford Mustang, 1972 Ford Mustang, 1973 Ford Mustang

Description

New water restrictor plate for the Mercury or Ford equipped with the 351 Cleveland engine. It has been an accepted fact for decades now that the 351C bypass system was not the greatest idea Ford ever came up with. The unique 351C thermostat "hat" never seals well, causing a certain portion of coolant to just circulate through the block and never make it to the radiator. Years ago, Pantera enthusiasts (all Panteras had cooling issues from the factory BTW) found that if they soldiered a penny into the hole in their restriction plate and used a standard small block Ford thermostat, their cooling issues all but disappeared. That trick worked fine until Ford discontinued the brass restrictor plate.

NOTE: The restrictor plate is installed "hat" down, as shown in the first picture above.

This aluminum unit is designed to replace the brass plate and be installed as-is. Simply remove the original brass plate and tap this one back in its place. This unit must be used in conjunction with a standard thermostat , you cannot use the 351C unique thermostat with this block off plate. The tiny hole in the center is for air bleed only. Want to find out how to use a penny instead of purchasing this plate? Click hear to learn more!

On a record hot day in Evansville, In at 108 degrees the car was driven a while. She never went over 200. Im so happy with this upgrade, get the WCCC part and a 160 thermostat and your problems are cured!

Replaces Ford Part number D0AZ-8K517-A.

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Shipping Details

Shipping Weight:

0.02 LBS

(weight shown may be the )

Shipping Dimensions:

34 Customer Review(s)

4.80

Out of 5

5 Stars

85%

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Morris Ray

Water restrictor plate

Solved the overheating issue and allows the use of a standard thermostat.

Reviewed Enumclaw, WA in on 7/30/2026

Alan Mach one 1973

Don't install this very bad "part" for taking care about your car !!!!

Well as far as I'm concerned after installing the restrictor plate, the case turned into a nightmare... quickly a cream formed in my radiator indicating that the cylinder head gasket had suffered! I'm in a black mess because of this stupidity and I don't know what to do. So by finding out more I learned that the 351 Cleveland had a particular specification at the level of its thermostat and that putting most of the thermostats sold for the 351 Cleveland is a mistake (the only true and correct thermostat for the 351 Cleveland is ROBERT SHAW 333 Series hi flow 333-6180) hence my heating problems that I wanted to fix after seeing on the West Coast site that there was this restrictor plate to avoid the heating problems of the 351 Cleveland!

Be careful !!! my car is brand new I just took it out of restoration a few months ago and now i have this big big problem i'm very furious of course !! while i absolutely need to change now my head gasket which is not an easy operation !!!

Reviewed France in on 2/6/2025

Lynn Koglin 1973 Cougar XR7

No more overheating!

Product worked as advertised! I wish I would have found this before replace radiator.

Reviewed Louisville CO in on 1/26/2023

Jim O 1973 Mustang 351c

It’s a Christmas Miracle! 73 Mustang 351cleveland

This was installed along with a 160 thermostat. Before the needle was always near the top end of the range near hot. Now after this it’s in the middle at the highest temp. It does exactly as it says. Bypasses so the coolant actually goes through to cool the engine instead of flowing back to the water pump. Highly recommend you get one of experiencing running hot.

Reviewed in on 5/28/2022

LCK

So far so go!

I put this in my 1973 Cougar 2 weeks ago. I have driven it about 100 miles. No more running hot at idle! I can't believe it took me years to find this product. I would highly recommend this if your 351 C is running hot. I would suggest WCC to have this populate when searching for cooling items for 351 C.

Reviewed Louisville CO in on 4/30/2022

Product Questions

Number of questions: 0

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