Ford Small-Block V8 Engine Swap - Swapping From Six To Eight
What do you need to convert a classic Mustang from a six-cylinder to a V-8?
Because we have performed a number of six to V-8 conversions in this magazine's 30-year history, you'd think we'd have it all down to a methodical process. However, each and every project brings its own challenges. Our '67 hardtop was no exception. We learned to plan better for one thing. We installed a JMC Motorsports hydraulic clutch along with a Master Power brake booster and discovered quickly the two will not work well together no matter what kind of modifications are made. That's when we went to a Modern Driveline cable clutch and Trans Am Racing power brake booster instead. Both cleared each other nicely.
We also learned about exhaust systems, headers, and pipe size. We needed a stock 2- or 2 ¼-inch dual exhaust system from Virginia Classic Mustang instead of the JBA system we ultimately went with. The JBA system is terrific and offers perfect fit. What's more, it yields a throaty bark with minimal backpressure. However, the JBA system is designed more for 400-500-horse small-block engines due to its 2 ½-inch pipes and straight-through mufflers.
Ride height is another issue we didn't address until the car was complete. We needed five-leaf mid-eye springs for more acceptable ride height. We went with four-leaf mid-eye and got less ride height than we bargained for.
The best advice we can offer to readers contemplating a six to eight conversion is to plan ahead and do your homework beforehand.