Bill Smith
Founder, 1929-2014
Speedy Bill
Since 1952
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Pro Shocks SM400 Chrome Mustang II Replacement Shock

SAME DAY SHIPPING! Most orders ship within 24 hours.

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Pro Shocks SM400 Chrome Mustang II Replacement Shock
Pro Shocks SM400 Chrome Mustang II Replacement Shock

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Pro Shocks SM400 Chrome Mustang II Replacement Shock



Q & A

What's in the Box

Stock mount style, modern gas cell shock. Fits where your original Mustang II shock went. Lower mount accepts a 7/16" bolt. Has a 10" ride height.


  1. The outside to outside measurment of the mounting pin/bushing is 3.38".

You may also be interested in:

Pro Shocks C-500 Stud Cover for Shocks
                        Polished aluminum. Trick way to clean up frame area on your Mustang II! Fits any 3/8" x 24 thread studs.
Mustang II Coil Spring Cushion

These are just like the stock Mustang II used on top of the front coil spring to eliminate noise and binding.

Mustang II Bolt-On Coil-Over Kit w/ Carrera Shocks

These kits provide the highest quality performance characteristics for your Mustang II front end. The unique "half barrel" shape springs are designed specifically for use with the Carrera coil-over shocks and the factory upper spring pocket. This enables the use of a longer spring, which allows for a lighter overall spring rate. By building the upper section of the spring to factory dimensions, this puts the weight back into the frame instead of on a single stud. 

  • For stock-to-2" lowered cars (no less)
  • Fixed, non-adjustable valving 
  • Developed for high performance with increased travel
  • Fully adjustable ride height using included aluminum spanner nut
  • Easy bolt-in installation
  • Unique spring fits the stock upper seat in the frame
  • Includes 2 chrome body shocks, mounting kit, 2 chrome-plated springs (choose specific rate)

NOTE: Not recommended for front axle weights in excess of 1900 lbs.

Spring Rate Chart (Link)

Coil-Over Mounting Guide (GIF)

Monroe Shocks 32118 Monro-Matic Plus Mustang II Front Shocks

Monro-Matic Plus shock absorbers are nitrogen gas charged and feature velocity sensitive valving and all weather fluid, which offers improved comfort at an economical price. Direct factory replacement shock (OEM geometry) for the Mustang II front suspension.

  • Compressed Length:  8-3/8"
  • Extended Length:  11"
  • Travel Length:  2-5/8"
  • 5/8" diameter piston rod is nitrocarburized for long service life
  • Large 1-3/8" bore provides more efficient and consistent control
  • All Weather Fluid contains special modifiers to reduce friction and ensure smooth rod reaction
  • Nitrogen gas helps maintain tire to road contact by reducing aeration
  • Special "Self-lubricating" fluid seal retains gas without excessive wear or friction
  • 2" reserve tube contains more fluid for consistent performance
  • Full Displaced Valving provides better valving range on both the compression and extension cycles of the unit for a smooth, comfortable ride
Mustang II Front Springs, 350 lb. Spring Rate, 13.5 Free Height

Our Mustang II springs come in rates from 275 thru 425 and in 13.5” free height/length. They will require cutting to the necessary length on the majority of applications. For the heavier vehicles such as full size pickup trucks and fat fendered cars the spring rate used will normally be in the 350-400 range. With Small Block and automatic a common rate is 375 to 400 and with the addition of A/C or a big block you will need to compensate for the additional weight and go to the next higher rate. Frame boxing and plating, accessories, and fuel tank size all play a part in selecting spring rate. When vehicle is sitting at ride height ready for test drive the lower control arms should be parallel with the ground or pointing down at a slight angle on the outer ends. The springs will settle some in the first couple of hundred miles so allowance for this should be made.

  • Powder coated gloss black
  • 13.5" spring length
  • Use the spring chart below to select proper rate

Use the following chart to select your rate:

  • 1200 lb. Front  End Weight = 275 Rate Spring
  • 1300 lb. Front  End Weight = 300 Rate Spring
  • 1400 lb. Front  End Weight = 325 Rate Spring
  • 1500 lb. Front  End Weight = 350 Rate Spring
  • 1600 lb. Front  End Weight = 375 Rate Spring
  • 1700 lb. Front  End Weight = 400 Rate Spring
  • 1800 lb. Front  End Weight = 425 Rate Spring