1967 Ford Mustang Engine Swap - Six-To-Eight Engine Swap

We mocked up our small-block with a Milodon oil pan, along with a Tremec five-speed to see how everything would fit the first time in.>>>

Even though the last '67 Mustang left the assembly line over four decades ago, you can still find relatively rust-free examples driving around the Southwest and West Coast regions of this fine country. While all the hi-po 289 models and Shelbys have long since been snapped up, there are many pedestrian inline six-cylinder ponycars left. Such was the case with CC's '67 Mustang that Editor Glad ran across two years ago on Craigslist, which we purchased for $2,000. It was a great example of grandma-bashed, since both ends were bent and it was plenty shabby in the middle. But all the basic components were in place. Over the past 24 months, we've been slowly resurrecting this notchback from its neglected state, and now that most of the bodywork is complete and the suspension is ready to do a little apex clipping, the next piece of the puzzle is to put some horsepower to it. We managed to not blow up the '88 Mustang 5.0L engine we used for the supercharger testing in the Sept. '07 issue ("Make 600 HP on Pump Gas"), so for now horsepower will come via natural aspiration.

Our first move called for the classic six-to-eight engine swap that car crafters have been practicing for almost as long as inline six-poppers have existed. For some cars, this swap is ridiculously easy, while others like our Mustang demand a few new parts to complete the swap. We thought it worthwhile to illuminate all the details involved with dumping the dead 200ci inline-six for our much more lively 390hp 5.0L. Plus, we'll include some great information on swapping in a Tremec T5 five-speed with help from Bruce Couture at Modern Driveline. We'll break this presentation up into several categories and fill you in on all the part numbers from the companies that helped us pull this off, so you have a very specific parts list that will help when it comes time to do your own version of the six-to-eight shuffle.

Engine
Our first task was to remove the original inline 200ci six and the automatic trans. Since the Car Craft shop was full to the brim with other projects, Tim Moore offered to help us with the swap. So with the epoxy primer barely dry from the body shop session, we began the destruction phase of our engine swap. Earlier in our suspension-upgrade session, we noticed that the six-cylinder's original engine crossmember was mysteriously missing. Knowing that we had to have a V-8 version, this was no great loss. An Internet search turned up Cobra Automotive, which offers not only a performance version of the engine crossmember, but also an outstanding reinforced manual steering centerlink that allows us to get rid of that clunky Mustang ram-assisted power steering. We'll save that for a future story.

First, we yanked the original 5.0L balancer and timing chain cover so we could use the new Year One '68 302 cover that offers a provision for the Edelbrock mechanical fuel pump. To our surprise, our 5.0L came with the fuel pump eccentric on the camshaft.

Professional Products offers a small-block balancer with a separate bolt-on, external, 50-ounce weight. The balancer also comes with both three- and four-bolt circles for mounting the crank pulley. Ford uses five different pulley depths that Professional Products offers spacers for, but this application requires no spacers.

We also removed the 5.0L Fox-body oil pan and replaced it with a Milodon oil pan, oil pump, drive, and windage tray to fit the Mustang chassis while also helping to control oil during those high lateral g maneuvers we have planned. To make it all fit, the oil pan must be installed before the scattershield.

We quickly ran up quite a list of parts needed to complete just the engine portion of this swap. Perhaps the most confusing part involves Ford's use of external balance weights on the harmonic balancer and the attendant accessory drive. All early Ford V-8 small-blocks used a 28-ounce external offset weight for both the harmonic balancer and the flywheel/flexplate until 1980, when Ford changed this value to 50 ounces. This was important for us since we would be using an '88 Mustang 5.0L engine. We also decided to go with a mechanical fuel pump assembly rather than mess with an electric pump at this time. This demanded some changes to the engine's front dress and a new front balancer. We found what we needed with a Professional Products balancer that includes both three- and four-bolt crank pulley bolt patterns, since Ford changed that bolt pattern along the way to make life interesting.