1988 Ford Mustang 5.0 Pro Stock Build - Pro Stock Pony Part 3 - Tech

Obviously, all that wonderful airflow supplied by the intake must find a way through the head ports as well. The E7TE heads were limiting the eventual power output of the motor, despite the benefit of having air forced through the intake ports by the HP turbo. Coming to the rescue was a set of heads from Trick Flow Specialties, which offered a multi-tude of benefits, not the least of which was lightweight aluminum construction. Right off the bat, the heads knocked more than 40 pounds off the curb weight, some of which was reinstalled with the slightly heavier SysteMAX intake (compared to the factory H.O.). In addition to the substantial weight savings, the aluminum construction improved the detonation threshold, an important consideration with a high-horsepower turbo motor. The trick Twisted Wedge design also improved the piston-to-valve clearance (compared to conventional inline heads with similar valve sizing), which allowed more lift and duration from our cam without fear of interference. It's paramount to check piston-to-valve clearance when installing a new cam profile and/or big-valve heads. The last thing you want is to ruin a perfectly good set of heads by having pistons permanently close all those shiny stainless steel valves.

The Trick Flow Twisted Wedge heads also offered improved flow rates compared not only to the stock E7TE heads, but also to the standard as-cast Twisted Wedge heads thanks to full CNC porting. The 185cc intake ports were a significant step up from the 170cc ports offered by the as-cast Twisted Wedge heads and a monstrous step from the tiny E7TE heads. The flow offered by the CNC-ported heads was right in line with the jump in port volume, as the 185 heads increased the flow rate of the as-cast heads from roughly 250 cfm to 300 cfm. The exhaust-port flow was equally impressive, as the CNC program stepped up the exhaust flow from 193 cfm to 231 cfm. These flow figures compare to just 160 cfm on the intake and 112 cfm from the E7TE heads. The numbers indicate that the 185 CNC Twisted Wedge heads from Trick Flow nearly doubled the intake flow of the stock heads and more than doubled the exhaust flow. Having successfully run 185cc heads (from various manufacturers) on many 302s, we were not worried in the slightest about excessive port volume having a negative effect on turbo response. As it turned out, the response was actually improved, and the new power offered by the heads, intake, and cam required the use of an even larger (and more powerful) turbo.

The final upgrade to our 5.0 turbo motor was a performance camshaft. Obviously, the turbo was working well with the stock cam, but there was much more power to be had with aggressive cam timing. We didn't want to go hog-wild with a solid-roller race cam, especially given our piston-to-valve worries, but we could improve top-end power, and power throughout the rev range, with the proper aftermarket cam profile. Given our concerns for piston-to-valve clearance, we went the conservative route.

Just because we couldn't run a wild cam profile didn't mean we weren't hoping for impressive power gains. The Lunati Voodoo lineup offered super-aggressive ramp rates to maximize the power gains offered for any given combination of lift and duration. The aggressive ramp rates helped improve the all-important average power production. As we've seen with this low-rpm motor, massive acceleration doesn't come from peak power numbers alone. The best motor combination is the one that offers the most power over the usable rpm range.