Square Body's

     1973-87 & SUV's up to 1991 GM trucks have had many nicknames such as Rounded Line and Box-Body but the most popular name today is Square Body. Chevy changed the C to an R and the K to a V in 1987-91 as they were being produced alongside the next generation of GM trucks. G10/20/30 Vans are 2WD and 4WD and can use the same LS conversion mounts from the same year C/K equivalent.

     In order to understand what conversion mounts you need for your swap, you need to first understand your vehicle and the differences throughout the years. In the following photo, 1 is the frame perch. You may also find it called towers, engine/motor stand, frame stand. Just because your Square Body currently has a V8 in it, does not mean the previous owner is using the OEM V8 frame perches. 

 

The motor mount and motor mount bracket in the following photo goes by a lot of names. A and B make up the Clamshell Style engine mount. GM refers to A as engine mount and B as a bracket. Nowadays, A is most commonly referred to as engine mount while B is most commonly reffered to as the Clam Shell. Engine mount is a loose term however and in order to not confuse the style of motor mount you have with the Early Style, you can refer to them as the Clamshell Mount. A can also be referred to as: rubber isolator, rubber mount, SBC/V8 engine/motor mount, "mounting, engine". B can also be referred to as: buckets, elephant ears, cups, motor/engine mount bracket, "bracket, engine mount", "bracket, engine mt". The Clam Shell Style started to phase out the Early Style Short and Wide/Tall and Narrow's in 1972.

1972 C10's with a BBC had the Clam Shell Style. All Square Bodies 73-87 (91) with V8's and Diesels used the Clam Shell Style. 

 

A- Clamshell Mount; B- Clamshell

 

The clamshell itself (B) is no longer available from the dealership but the clamshell mount is still available at local parts stores. OER and other companies make reproduction 2WD clamshells but you have to understand that they are not a one size fits all. 2WD and 4WD clamshells will not interchange for instance. Clamshells are passenger/driver oriented as well. It is good practice to label them if you are removing them to install newer clamshell mounts to avoid any confusion later. You do not need to worry about acquiring the correct clamshell when using our EZ Mount conversion mounts. 

Square Body's with a SBC  used a 4-bolt clamshell mount while BBC's and Diesels used the beefier 3-bolt clamshell mount. All V8 frame perches have the bolt pattern for either clamshell mount. 4-bolt clamshell mounts have all four corners flush on a flat surface, but only three bolts are used to mount it to the frame perch. 3-bolt clamshell mounts use the top two corners and the middle on the bottom. The rivet/crimp wholes and mounting holes are reversed on the bottom of the 3-bolt clamshell.  

          A- Mounting bolt holes that are flush to the engine crossmember. 

          B- Rivets/crimp holding the clamshell together.

 

 

V8 Clamshell Mounts 

4-bolt SBC (rubber):  WESTAR EN2292, DEA / MARMON RIDE CONTROL A2292, ANCHOR 2292, PIONEER 602292, GM GENUINE 22188497

4-bolt Energy Suspension Poly Insert: 3.1116G (Black), 3.1116R (Red)

 

3-bolt BBC/Diesel: WESTAR EM2395, DEA / MARMON RIDE CONTROL A2395, ANCHOR 2395, PIONEER 602395

3-bolt Energy Suspension Poly Insert: 3.1121G (Black), 3.1121R (Red)

 

Poly Insert Install Instruction

 

 

 

 

V6 frame stands

If Your truck was originally a V6 you will need to install V8 frame stands from a 1973-87

 

 

Conversion Motor Mounts

 

Dirty Dingo EZ Mounts are designed to bolt to the engine and the CNC cold rolled steel tabs will wrap around your stock clamshells. No clamshell that is NLA or modfications required! No more hassle acquiring the correct clamshells! These mounts will allow you to move the engine from the original bell housing position up to 2 1/2 inches forward, and up to 1/2 inch rearward. Low mount AC will fit but you will need to mount the engine forward from the original bellhousing position.

When installing the LS engine into 4X4 truck the front drivers side cross member might need a slight notch. The front oil pan may slightly touch. It is so minor that some choose to heat it up and massage the engine crossmember with a hammer. It is better to clearance the engine crossmember to keep your stock driveline angles rather than jacking up the motor mounts. It is not reccomended to move the engine as far forward as possible for low mount AC to clear the engine crossmember as it ruins the angle of your front driveshaft. For longevity and performance, move the engine back and get relocation accessory brackets if needed. 

     

 

Engine Accessories

There is a lot of room in C10s and most accessory brackets fit other than stock LS compressors (without notching the frame). Dirty Dingo low mount ac for LS GEN III/IV clears the frame, it may require moving the engine slightly more forward than stock position. Truck spacing would move the bracket to the furthest forward mounting hole and allow you to push the engine back further than Camaro or Corvette spacing would allow you to go. 4WD frames have an upraised arch around the wheel well and make low mount ac much more difficult. You have to chop more of the frame compared to a 2WD frame. Low mount AC is not recommended in 4WD frames as you have to move the engine so far forward to clear the engine cross member itself as it ruins the angle of your front driveshaft. For longevity and performance, move the engine as far back as possible and get accessory relocation brackets if needed. 

 

 

Dirty Dingo low mount ac setup fits without any notching although it still requires you to move the engine forward from stock position. Fits best in truck spacing as that mount bracket further away from the motor mounts. 

If your factory AC compressor has a high pressure cut of switch we recommend using an aftermarket Four seasons retro add on switch kit- Here.

 

 

 

 

 

 

Additional helpful links:

 

https://www.cartechbooks.com/how-to-restore-your-chevy-truck-1973-1987.html