1978 Mustang with a Nissan Turbo Inline-Four

1978 Mustang with a SR20DET Inline-Four

Jason Bowman purchased a 1978 Ford Mustang II Mach 1 in 1992 when he was 18 years old. Over the years it has seen a full restoration and several engines. However it’s the last engine choice that really separates this Mustang from the herd.

1978 Mustang with a SR20DET Inline-Four

1978 Mustang with a SR20DET Inline-Four

The Mustang ran several Ford 302 ci V8 engines with the last having a .060 overbore. The engine had a hard time staying cool even with an aluminum radiator and electric fans. The three-speed automatic transmission didn’t help either, especially on the highway.

1978 Mustang with a SR20DET Inline-Four

1978 Mustang with a SR20DET Inline-Four

When Jason started considering another engine, he knew he wanted fuel injection and if possible drop some weight in the front. He also wanted taller gears only a five or six-speed manual could only deliver. Jason thought back to a 2.0 L SR20DET inline-four he installed in another vehicle and how well it performed. He realized the Nissan engine and accompanying transmission would solve his issues.

1978 Mustang with a SR20DET Inline-Four

Originally Jason wanted a SR20DET and six-speed manual from a Nissan S15 but the Importer recommended using a Nissan S14A because it comes with a T28 ball bearing turbocharger and stronger five-speed manual.

1978 Mustang with a SR20DET Inline-Four

Installing the inline-four into the Mustang engine bay required custom mounts that connected to the factory mount points. Even though it probably will never be turned back to a V8, Jason felt good knowing it still could. He also switched to a Subaru Justy alternator and Spriso Motorsports mount because the factory Nissan alternator and mount was too large.

1978 Mustang with a SR20DET Inline-Four

1978 Mustang with a SR20DET Inline-Four

Jason upgraded the engine with a Nissan 300ZX mass air flow sensor, FiveO 550 cc injectors, and ECU tune by RS-Enthalpy. Jason estimates the engine produces 275+ horsepower and 245 lb-ft of torque. To keep the front looking stock Jason opted for an air-to-water intercooler inside the engine bay.

1978 Mustang with a SR20DET Inline-Four

1978 Mustang with a SR20DET Inline-Four

The five-speed manual transmission was installed thanks to a modified Mustang II crossmember and GM transmission mount. Since the Mustang originally came with an automatic transmission Jason needed to build a clutch system. He built it using a Nissan 240SX master/slave cylinder and custom linkage.

1978 Mustang with a SR20DET Inline-Four

1978 Mustang with a SR20DET Inline-Four

1978 Mustang with a SR20DET Inline-Four

The transmission connects to the factory Ford 8″ rear end via a custom driveshaft.

1978 Mustang with a SR20DET Inline-Four

1978 Mustang with a SR20DET Inline-Four

Jason upgraded the front brakes with KVR 11″ slotted rotors and Hawk HPS pads. The wheels are five-lug thanks to an Allstar Performance brake kit that uses Ford Granada rotors, custom brackets and GM metric calipers.

1978 Mustang with a SR20DET Inline-Four

1978 Mustang with a SR20DET Inline-Four

Inside the cabin Jason made a custom dash from aluminum, fiberboard, and fiberglass. The dash holds a rail Tech Vapor all-in-one dashboard flanked by AEM wideband and boost controller gauges. Below that is a series of toggle switches to control functions like lights and wipers.

1978 Mustang with a SR20DET Inline-Four

1978 Mustang with a SR20DET Inline-Four

Jason’s Mustang has given him many years of enjoyment and thanks to his tremendous work it will continue to do so.

1978 Mustang with a SR20DET Inline-Four

3 Comments

  1. Peter

    Looking through the pics, reading the descriptions, yes, I really like this Mustang….then come across the interior shot…..nope nope nope nope nope.

  2. Bryan OShaughnessy

    Nice work; I’m sure it gives the owner a lot of pleasure driving it, showing it, and knowing that all that hard work (and money) was a success. I have to wonder, though, what is it that makes an owner invest that so much time and treasure to make a half-breed like this? No criticism intended, but he surely won’t get all his time and treasure investment recovered, no matter how much/little he sells it for. And how satisfying can a car be???

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