5.0 Mustang & Super FordsHow To Engine
Two-Valve Mustang Buildup - Double Stuff
Getting Twice The Power From A Two-Valve With More Flow And 15 PSI
Horse Sense: Not only does Patriot Performance offer Stage II and III ported versions of the Romeo and Windsor Two-Valve heads, but bare and assembled versions of its own 185cc small-block heads for 5.0 and 351W engines are also available.
After bouncing around Gulf Coast Dyno in Sarasota, Florida, we took a moment to lament that we'd been so caught up in keeping with the S197 mania while not forgetting our Fox roots that we really hadn't done much 4.6 Two-Valve stuff lately. So we asked Ray Walker if he'd be up for playing around with a Two-Valve combo. Naturally he was, and he even had a white '01 GT sitting in the corner of the shop. Our idea was to throw the book at a Two-Valve and build a powerful, streetable combination.
It's tough to reel Ray into building something mild, as his mind instantly thinks of pegging the boost gauge. So we compromised at building an off-the-shelf combination and topping it off with a single-turbo kit. It seemed simple enough. We'd bolt it all together, make big power, and everything would be cool-and ultimately it was.
We should have put stouter springs in our ported heads to work with the boost. Of course, when you boost an engine, the increased cylinder pressure makes it harder to open the valves. Since boost rises with rpm, it only makes it harder on the valvesprings at high rpm. Hey, we all make mistakes and overlook the small stuff from time to time, but we're man enough to admit it. Besides, we still managed to more than double the Two-Valve's output. The car is super-streetable, plenty fast, and should be bulletproof since it can't rev to the moon.
Besides, as Ray put it, "400 rwhp is enough to run mid-11s with a good driver and a five-speed." Most people would be plenty happy with that kind of power, but if you're jaded like us, throw in more aggressive valvesprings and have even more fun.
A stock Two-Valve 4.6 doesn't exactly make a performance enthusiast swoon, but it does hold the potential to really build some power. Knowing we'd be pumping up the power well beyond the levels the stock short-block could handle, Gulf Coast Dyno's Ray Walker filled the stock block with 8.5:1 CP pistons, Manley rods, and a Cobra crankshaft. Besides a Terminator dual-pump fuel tank to feed what we planned to throw at it, the rest of the combo was stone-stock.
First we moved to replace the stock Two-Valve heads with a set of Stage II-ported Windsor heads from Patriot Performance (PN 1004W; $1,295). These are fully assembled CNC-ported castings that feature a five-angle valve job, stainless valves, bronze guides, 0.600-inch lift springs, and titanium retainers. They're said to flow 215 cfm and are also available bare if you want to go with your own spring/valve/retainer package. The bare versions ring up at $1,095. Prelube the cams before getting out the torque wrench.
Patriot recommended Comp Cams 262H (PN 102100; $620.23) cams for its Stage II head package. The cams spec out with a duration of 224/232 at 0.050, a 0.500-inch valve lift, and a lobe separation of 114 degrees. These are direct-replacement cams offering a smooth idle but still lets you know the car has cams. It's said to pull from 1,500 to 5,200 rpm. Ray torques the cam towers to the factory 87-lb/in specs.