Muscle Mustangs & Fast Fords
Brodix CNC Ported Cylinder Heads Install - Project ProCharged - A Head Above The Rest
Fresh off the Ultimate Guide to Cylinder Heads, our set of Brodix ST 5.0R lungs is bolted onto a supercharged small-block and produces spectacular results.
Before we get into the nuts and bolts of this tech article, we want to tell you about the events that led up to it, as they were primarily the driving force behind testing the Brodix cylinder heads in the first place. Oftentimes, tech stories are hatched within the confines of the top-secret editorial meetings at MM&FF Command Central. This story, on the other hand, was borne out of the need to send the nearest competitor packing.
The trash talking started in early summer as we recall. Associate Tech Editor John Hedenburg got the whole challenge rolling with Don King-like flair. Comments were fired from office to office, either by e-mail or verbally. "The preposterous power of the pony shall prevail in this perilous time," touted the big-wigged Hedenburg. Conversations at lunch and at editorial meetings did not go unscathed either, and dyno results were repeatedly posted on opponents' doors, as the scale of horsepower increased each week leading up to the track date.
You see, we share office space with GM High Tech Performance magazine and its editor Rick Jensen, who happens to own a hopped-up Buick Turbo T Regal, and Hedenburg had put our resident '90 supercharged Mustang GT up against said Buick in quarter-mile competition. Rick had already lost his first match race against our '99 Lightning project truck, alias The Fridge, a year earlier and was looking to repair his racing reputation.
His turbocharged six-cylinder had just received a new high-performance intercooler, a rebuilt transmission and a stall converter, and he hoped to improve on its best of 12.34 with those modifications. Rick also feeds the Buick a healthy diet of 116-octane race gas and some 24 psi of boost. Subsequently, it was up on the Mustang by about 10 hp and a stout 60 lb-ft of torque.
Our Fox GT, wearing 17-inch BFG drag radials and burning nothing but pump gas, was running stout 12.25s at 115 mph with its ProCharged 143,000-mile 302 motor; however, some unplanned drag passes at the MM&FF 2003 Two-Valve Shootout resulted in the coolant gushing out of the overflow tank. There had obviously been a breach in the high-mileage head gasket. That wouldn't have been a problem except for the Buick shootout was scheduled for the following week. It was decided that as long as the heads were coming off it would be a shame not to upgrade, and a few extra oats in the feed bag wouldn't hurt either.
Editor Campisano placed a call to the reigning engine dyno king of late-model Fords, our own Richard Holdener, who offered to next-day-air us a wicked set of M2 CNC-ported Brodix ST 5.0R cylinder heads. The aluminum Brodix units had produced a stout 434 hp and 410 lb-ft of torque on a carbureted 331ci motor (MM&FF, November 2003) so we knew there was plenty of potential. Holdener also supplied us with an E303 camshaft to make the most of the improved induction, but the combination of stock pistons and 2.02 intake valves left us with a mere .018-inch piston-to-valve clearance. This obviously would not play, so back in went the stock camshaft, .444-inch lift and all.
The ST 5.0R heads come with 171cc intake ports and 60cc chambers, but the M2 versions feature 2.02/1.6 valves versus the 1.94/1.6 arrangement, and the intake ports grow to 185 cc while the chamber volume rises to 66 cc (which was great for our supercharged application). According to Holdener's flowbench tests, the Brodix heads flowed 277 cfm (.600-inch lift) on the intake and 222 cfm (.650-inch lift) on the exhaust.
Brodix delivers the assembled heads using top of the line hardware from Comp Cams. One-piece stainless valves and titanium retainers are standard equipment and improve the overall durability of the units. Installation was fairly straightforward, and all of the accessory bolt holes have been drilled so you can have all of the comforts that your street car provides, while having plenty of horsepower-making airflow. There's even a provision for the stock air tube at the back of the heads for the smog-conscious individual.
The ST 5.0R heads utilize stock length 6.250-inch pushrods and 7/16 roller rockers must be employed. Since our heads were set up with guideplates, we used the recommended hardened pushrods from Comp Cams. Holdener had also changed the rocker arm studs to 3/8-inch pieces, which we switched back to 7/16 in order to use the Comp Cams 1332-16 Pro Magnum roller rockers that we had.
"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.
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.