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.
![](https://onallcylinders.com/wp-content/uploads/2023/04/29/Summit-Racing-LS-engine-replica-block-front-1024x800.jpg)
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](https://onallcylinders.com/wp-content/uploads/2023/04/29/Summit-Racing-LS-engine-replica-block-top-1024x953.jpg)
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.
It would be perfect for my Swamp Swap ! Say that 3 times as fast as you can,… lol. I am installing a BBC 454 Gen IV in a 90′ 1/2 ton 4×4 Suburban for the mud boggs this summer. Should be a blast. The mockup will make the positioning of the engine so much easier. Keeping the 700R4, slightly modified :)… I was thinking forged pistons, new rods, and main bearings, and balanced rotating assembly. Pitch the heads, and go with a set of Dart, or equal performance aluminum head’s, with an embarrassing at the stop light lift, roller cam and rockers, dual chain,… wait , maybe even a noisy gear drive,.. have to think about that one,..lol. Top it with a dual plain, and at least a 780 or 850 carb. I sure could use some advise from you all, as long as its nice advise,..lol with horsepower… I want an “Earth Shattering Hell Ride” someting that will shake the ground I drive on. Thanks for even reading this wanna be, and I already have plenty of “SUMMIT” stickers for the bogger ,.. Looking forward to your input.