The author removes the factory E7TE heads. We found no evidence of a blown head gasket, bu
"One of the best features of the ST 5.0 is that it is not limiting," said Mark Fretz of Brodix. "A guy can buy these for his street car and as it gets faster, the heads have room for larger valves and porting. Our heads usually cost more than our competitors', but the quality of the casting can withstand lots of boost and nitrous."
The M2 CNC porting is good for a 35-cfm increase on the intake and a 26-cfm increase on the exhaust. "Our flow numbers are achieved using a standard 4-inch bore and the stock dowel and head bolt locations. It's the only way to get the true flow numbers of the heads," noted Fretz.
Prior to the cylinder heads, the high-mileage Windsor engine picked up nearly 40 rwhp with an Edelbrock Performer intake manifold, and we knew that a set of good heads would be worth quite a bit as well.
After the head installation, we tooled on down to LaRocca's Performance in Old Bridge, New Jersey, where we strapped the GT to the dyno to get some numbers. We've had the crew there tune our ProCharged pony since we put the blower on it, and had been there to establish a baseline prior to the cylinder head installation. Those baseline figures were 383.5 hp and 407 lb-ft of torque at the wheels. Before we could make a full run though, Jim LaRocca had to retune the custom chip, as the improved airflow made the air/fuel ratio extremely lean.
Hedenburg uses a gear puller to take off the harmonic balancer.
Once LaRocca had his prescribed ratio, the power output jumped dramatically, resulting in 473.1 hp and 474.1 lb-ft of torque. That's 90 hp at the rear wheels, folks.
And what became of the Mustang vs. Buick shootout you may ask? The shootout was the same day we were at LaRocca's bringing the car back into tune and getting our after-modification figures. When we finally got the Mustang to the track, the ambulance crew had been mysteriously sent home early, and the Buick never made it into the 12.20 zone.
We couldn't make any passes that day, but on Halloween we trekked back to E-town for some runs on our drag radials but neither the tires nor the track could hold up to the brute power.
The following week we returned for a track rental with some 26x10.5/16 M/T ET Streets in hand. Both the Buick and its owner were on hand to witness the 11.47 and 11.43 passes at over 123 mph. We played it off as fresh head gaskets and a good tune-up, but the 8-mph improvement told otherwise. Did we win the shootout? That's still being debated on a daily basis here at the office. We did, however, come out on top thanks to our Brodix M2-ported ST 5.0R cylinder heads.
The water pump and timing cover are next to come off.
As you can see, there was far too much play in the well-worn, 143,000-mile timing chain.
We replaced it with this Comp Cams Magnum double roller piece. We also used Pro Magnum 1.6