If you’re swapping an LS engine into a vehicle that didn’t originally have one, then there’s a good chance you’ll have to do a ton of fitment work to make sure it slides into the engine bay.

That’s why a mockup engine replica block can be so dang handy—and why you’ll be really interested to hear about some of the advantages of this LS Replica Engine from Summit Racing.

A lightweight replica engine block is a critical tool for an engine swap, because you can make sure the motor (including headers, intake, transmission, accessory drive) has the proper clearance without having to manhandle the heavy iron/aluminum block around the engine bay.

(Image/Summit Racing)

For starters, it can be disassembled for storage, so you don’t have a big honkin’ engine block replica taking up space in your garage all the time.

Secondly, it’s made of steel instead of foam. That means you can do some welding (like fabricating engine mounts) right against the block without damaging the mockup.

Summit Racing’s LS mockup engine block is, functionally speaking, a dead ringer for a Gen. III or a Gen. IV LS engine with cylinder heads installed—so all the critical bolt holes are in the proper places. That includes the header, oil pan, water pump, motor mount, transmission bellhousing, and starter mounting bolt holes. (And if you need to add a custom hole? Just drill it.)

Summit Racing LS engine replica block, top
Take a close look and you’ll see this made-in-the-U.S.A. replica block is held together with a clever system of tabs and slots, instead of traditional bolts. That’s because the tab-and-slot method offers superior rigidity once it’s all put together. (Image/Summit Racing)

But our favorite part?

Once you get your LS Swap done, you can plunk your Summit Racing replica engine down in the middle of your living room, go to the hardware store for some plywood, and you’ll have yourself an oh-so-classy coffee table too!

…But you may want to check with your S.O. before moving ahead with that plan.

Get a Closer Look at the Mockup Block & the Assembly Process in This Quick Video