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On a long enough timeline, it seems like just about anything is a candidate for an LS-swap. And now, the Grumman LLV mail truck can be added to that list. Someone has actually placed a 6.0-liter LS engine into a USPS delivery vehicle. Giving it more power than it was ever supposed to have. This swap was done by David Stacy a few years ago to give the LLV a serious bump in power. It was also featured at LS Fest, which is a celebration of all things fast and power via this powerplant.

Can you LS-swap a Grumman LLV?

Apparently, the answer to the question is yes, as it has already been done. Stacy was able to track down an old Grumman LLV to be used as a candidate for this daring project. According to LSX Magazine, the project took about two years of planning but the project itself lasted three months. Allowing this truck to make it to the 10th annual LS Fest. 

Before this project, equipping an LS engine to an LLV mail truck had not been done. So Stacy was pretty much in unknown waters as the project progressed. Nonetheless, the 6.0-liter LS V8 engine was able to give this delivery vehicle serious power. In the video below, the LS Grumman LLV shows off just how powerful it is. 

After tuning was complete, Stacy’s postal truck made 584 horsepower and 600 pound-foot of torque. Those numbers are much more than what the standard 2.5-liter “Iron Duke” engine makes in your typical LLV. 

Should you buy a Grumman LLV?

If you are interested in undertaking a similar project, it is possible to buy a Grumman LLV mail truck. But, it’s not as simple as checking your looking classifieds or visiting a used car dealership. Typically these vehicles are sold at government auctions once their life cycle is complete. Allowing the general public to experience a purpose-built mail truck. 

A USPS mail truck sits in a local neighborhood.
Grumman LLV | IFCAR

As the Grumman LLV is phased out in favor of the Oshkosh NGDV, there will likely be more old mail trucks popping up for sale. And hopefully, folks as crazy as David Stacy decide to test just how much power these old trucks can handle. 

Who is building the new mail truck?

After years of debate, Oshkosh Defense was selected as the company to build the new USPS mail truck. Known as the Next Generation Delivery Vehicle, or NGDV, this truck comes with either a traditional combustion engine or an EV powertrain. 

An Oshkosh NGDV mail truck delivers the mail.
Oshkosh Next Generation Delivery Vehicle | Oshkosh Defense

These new mail trucks are not here yet, but the United States Postal Service has placed its order. So, by 2023, some of the aging Grumman LLV fleet will start to be replaced. This is something that mail carriers are sure to appreciate, as the LLV has been in service since the 1980s, and they are certainly starting to show their age. 

The NGDV will have modern safety tech, slightly better efficiency, and should overall just be more comfortable than the old mail truck. Plus, as the LLV is replaced, more auto enthusiasts will be able to do crazy projects with them.


A Short History of the USPS Mail Truck