Basic Fabrication Steps for an LS Engine Swap

The power and versatility of the Gen III/IV Chevy power plant is no secret. The engine’s relatively compact external dimensions compared to its displacement and power output makes it one of the most desirable engine swaps out there. From hot rodders to tuners, it seems just about everyone is dropping the LS engine into their ride—and our shop is no different. Since the swap is so popular, we have decided to provide you with a quick “how to” when it comes to the basic fabrication one might encounter when fitting an LS engine into your engine bay.

1960 Cadillac Coupe: Taking The Engine Out

The project we have on hand is a 1960 Cadillac Coupe ( <<<<< click for the full restomod build gallery) receiving a 6.0L LS implant. In our case, the stock front cross member on the Cadillac does not allow the LS engine to sit low enough in the engine bay, so we swapped in a Heidts front cross member. Below you will find the basic steps we followed along with some things to be considered as you move along.

Smooth Firewall

The first thing we did after taking out the engine was smooth down the firewall. This gave us a little more room for our engine swap.

Stock Cross Member

Track Width Considerations: The key to a good cross member front suspension graft is maintaining the original track width, the distance between the right and left tires, as closely as possibly. If the stock track width of the chosen resto mod is say 62″, then a plus or minus 1″ is acceptable. Adhering to the 1″ rule will avoid wild wheel backspacing to compensate.

Notching and Toothing

The new frame section needs to be toothed (stepped) into the existing frame to assure multiple areas of weld joints. A slip bar (telescoping) piece inserted to the original frame and into the new frame section will allow you to have additional weld area and ultimately more strength in the graft.

Measuring and Squaring

Our front frame, crossmember, vender of choice is Heidts. We choose this product for its engineering and visibility. The cross member frame section gives you the ability to install engine mounts for a variety of power plate choices from L-S, Ford or carburated engines. The Heidts cross member will give you the custom choice to have the engine forward or rearward to fit the engine compartment, accommodate headers and achieve a unclustered engine bay.

Cross Member Installation

Coil Spring Hats Installed

Front shock and spring choices for the Heidts cross member: Available in coil over or spring and shock allowing you to choose the overall feel and also the ability to set ride height. For an air-bagged suspension, this set up is also available.