1968 Ford Mustang Engine Swap

Once centered, the engine is then leveled side to side as well. Ensuring the engine is level prevents issues with a multitude of things including shift linkages, hose fitment, fuel feed (carb'd applications), and more.

Finally, from under the car, the engine and transmission angle is measured and set using a quality floor jack that doesn't bleed down. You don't want your measurement changing slowly while you're elsewhere working on the car.

With the engine and transmission measurements "locked in," the Mustang Shop mount kit is mocked up against the Heidts crossmember. Due to the engine setback, the mount legs ended up sitting rearward of the main crossmember by about half their width.....

....The mount legs are notched to fit against the crossmember, clamped in place, and then tack welded. You don't want to do any finish welding as you'll build too much heat in the mount and melt the bushings.

To realize just how wide the modular engines are, you can see that the left cam cover just barely clears the master cylinder mounting holes, while the passenger side cam cover completely covers the heater....

....hose and A/C line openings and encroaches on the blower motor opening. No worries though, as our aftermarket A/C unit allows for custom hose routing/length so we can route them farther to the right or even through the cowl side.

Tacked in place for now, Classic Creations' Danny Gaydos (who has been behind the MIG welder for this whole project) made up this simple firewall patch with two bellhousing bolt access holes. The remainder of the firewall patches will be handmade and welded into place once the engine is back out.

When we first replaced our Mustang's floorpan we opted to leave the crossmember out between the two front floor supports. This is normally where the factory trans crossmember is bolted to, but we knew with our five-speed automatic we'd be adding a custom crossmember. The Ron Morris Performance Unicross crossmember was the perfect answer. This part is the Superman of crossmembers, allowing you to bolt in just about any transmission you can think of.

The Unicross is a simple measure, drill, and bolt-in affair for most projects. After getting our driveline angle determined earlier, it was a matter of fabricating a trans mount for the new-fangled 5R55S (it has but a single threaded lug and Gaydos modified a classic Mustang....

.....mount to work) and then affixing the Unicross to the mount. This determined where the crossmember's mounting brackets would go on the floor supports; a couple of drilled holes later and our transmission was secure.

Now that the engine mounts were completely tack welded and the Unicross crossmember located and its mounting brackets bolted in, the 4.6L Three-Valve could be removed from the engine bay once again to allow final welding of the mounts.

Gaydos fabricated small corner gussets for the mounts, from the main mount leg to the support bar (shown here) as well as from the main mount leg to the Heidts crossmember while finish welding all of the mount's contact points with the crossmember and the framerails.

A quick pass with the grinder cleaned up the finished welds. While not seen by most people, especially once the engine is in place, all of the engine compartment welds will be body worked and smoothed before applying body color paint to the engine compartment.

Taking a step back, we can see just how much room the typical Mustang II frontend, with the shock towers fully removed, really offers for engine fitment. The firewall will be partially smoothed and other small details will be attended to in order to make the engine compartment ready for painting.

We can't forget the engine side brackets of the mount kit either. These were tack welded together when the engine was in place. Here Gaydos has removed them from the engine and is finishing welding them.

After taking the engine in and out at least four times, we're getting pretty good at it. Once again the engine is dropped in place and the mounts bolted up to check for fit. Everything lined up nicely and the mount's through bolts slid right in. We'll be taking the engine out again once we get the project back to HQ.

When it comes to engine swaps, probably one of the most troublesome areas to tackle is the exhaust. It's tough enough installing an engine that was never factory installed in your project, but then throw in possibly lowering the engine or setting it back in the engine bay and it gets worse.....

....We thought we got lucky when we test fitted a set of BBK long-tube headers designed for the '05 and up Mustang. The driver side header, shown here, fit like it was designed for the swap, but when we tried to bolt up the passenger side header our luck ran out. Several dimensions just didn't work in our favor. We're still trying a few ready-made options, but we might be heading down the path of custom-made headers. Stay tuned for more.