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Ford X2 Heads and Holley SysteMAX Intake Install
When Ford Performance Parts introduced their new “X2” aluminum cylinder heads for small-block Fords, we knew they would be perfect for our 1995 Mustang GT project. Why?
Many aftermarket suppliers have stopped offering heads that accept the factory-style, bolt-down rocker arms in favor of provisions for typical stud-mount rockers. But most stud-mount rockers require aftermarket valve covers, and most aftermarket valve covers interfere with the alternator on 1994-1995 cars. So, stud mount rocker arms require a series of parts that make them less than a bolt-on for SN95 pushrod engines. But, Ford Performance Parts’ X2 aluminum cylinder heads utilize Ford’s bolt-down rocker arms, which means we can re-use our factory rockers and valve covers. Problem solved!
Sold as part number M-6049-X2, the cylinder heads are cast from all-new tooling. They’re a bolt-on replacement for the factory cylinder heads on most late-model 302s that feature better-flowing intake and exhaust ports, larger valves, ovate beehive valve springs, and a modern combustion chamber design. The X2 heads accommodate cams with up to up to 0.600-inch valve lift and are twenty-five pounds lighter per head than our production heads. That’s a full fifty pounds off our Mustang’s front wheels!
Besides weighting half that of the cast iron heads, the X2 cylinder heads are also lighter on our wallet. Since X2 heads utilize the factory bolt-down rocker arms, we didn’t have to buy stud-mount rockers, guide plates, hardened pushrods, and bigger valve covers.
To seal the heads to our 113K-mile short-block, we chose Ford’s head gasket and bolt kit (PN M-6051-D50) and intake manifold gaskets (PN M-9439-A50). A set of Ultra-Seal header gaskets (PN 5930) from Mr. Gasket completed the job.
It would be a crime to choke the Ford Performance X2 heads with the stock intake manifold, so we chose Holley’s venerable SysteMAX intake manifold instead. We opted for Holley’s new black powder coat finish (PN 300-72BK) for visual twist on this old favorite. Holley sent along a set of 30 lb/hr fuel injectors to complement our engine’s new power potential.
We could’ve attached the throttle-body to the intake manifold Fox-body style, but we wanted to retain our cruise control and emissions equipment. A throttle-body adapter from Trick Flow Specialties put our throttle body in the right spot and bolted up to our factory EGR system.
After all the parts were bolted up and the engine running, we took it to Delk Performance in Lebanon, Tennessee for a few finishing touches and a tune. Brent Delk is one of the few that burns chips for old-school cars like ours. (Today, tuners plug into the OBD-II port to tune the engine control unit. But, our 1995 GT is the last year of the EEC-IV, which requires an actual chip to be programmed and plugged into the ECU before each tune takes effect.)
Delk added an 90mm SCT Big Air mass air flow sensor that he tuned with our Holley 30 lb/hr injectors on their in-house Mustang chassis dynamometer. The result was a very respectable 274 horsepower and 310 lb-ft of torque to the wheels. Besides being 67 horsepower and 47 lb-ft more than our previous best, these numbers were through the stock AODE transmission and with all the factory emissions equipment in place, including the stock H-pipe. We’ll take that all day long.
Delk also modified the automatic transmission’s shift strategy, programmed the cooling fan to come on sooner with our 180-degree thermostat, and raised the rev limiter.
With the newfound power from our Ford Performance Parts X2 heads and SysteMAX intake, our 1995 GT is a hoot to drive. The reprogrammed AODE shifts later, harder, and the converter only locks up in overdrive. While the stock heads and intake ran out of steam at 5,000 rpm, this new combination pulls hard to 6,000 rpm.