Out-of-the-Box Performance
The Brodix-HVH heads represent something else that is becoming the norm in cylinder head technology: For all intents and purposes, these heads are race-ready right out of the box. Brodix casts the heads at their own foundry, using 356 aluminum, and then heat-treats them to a T6 condition. Cylinder heads such as this are designed with revised spark plug locations, incorporate decks with a minimum thickness of 9/16-inch, and include heavily reinforced rocker stud bosses. Aside from being CNC-ported by HVH (with impressive flow figures to match), these heads include threaded inserts for the rocker studs, providing superior strength and durability. The seats are hardened (which means you can use unleaded fuel, but that's another topic) and cut on Serdi equipment. The guides are bronze-walled. The combustion chambers are fully machined.
These CNC-ported big-block...
These CNC-ported big-block heads are available with and without valves. In this case, the heads shown do not include valves, however, the heads are sized for 2.25-inch intake and 1.88-inch exhausts. Intake valves with a 0.250-inch longer stem length and stock stem length exhausts are recommended. Note the bronze guides. The heads are engineered to accept 11/32-inch stem diameter valves.
Valvespring pockets on the...
Valvespring pockets on the Brodix-HVH big-block head are machined to accept 1.540-inch-diameter springs. Typically, the head can be machined for a larger 1.626-inch-diameter spring, as long as the pocket depth is not increased.
The bowl area of the Brodix-HVH...
The bowl area of the Brodix-HVH head has seen a considerable amount of CNC-machining, on both the intake and the exhaust side (the bowl of the cylinder head is the area of the port immediately behind the valve head). The bowls in most cylinder heads are bored with a vertical mill.
In the case of the big-block Chevy heads shown, they're designed to accept a set of 11/32-inch stem stainless steel valves (2.25-inch diameter intake; 1.88-inch diameter exhaust). The intake valves are 0.250-inch longer than stock, which allows the use of any number of aftermarket springs (pockets are cut for 1.54-inch-diameter springs). Because of the longer valve stem and, consequently, the greater installed valvespring height, pushrod length must be checked when these heads are installed on an engine. Both Brodix and HVH recommend the use of two-ring positive seals for 11/32-inch valve stems and 0.531-inch guides. The rocker studs are 7/16-inch examples, which are fully machined. You can use a common aftermarket roller rocker or a shaft arrangement from Jesel.
Typically, this leaves a sharp...
Typically, this leaves a sharp transition to the balance of the port, which in turn can create turbulence and port restrictions. Proper modifications to the bowl area (such as this) can contribute to as much as 35 percent of the total flow of the port.
The cylinder head will accept...
The cylinder head will accept a conventional roller rocker assembly, using an equally conventional 7/16-inch rocker stud. It can also accept a shaft rocker setup (for example, Jesel). Be sure to specify a rocker for a Brodix -2 head.
Brodix casts the heads at...
Brodix casts the heads at their own foundry, using 356 aluminum, and then heat-treats them to a T6 condition. Race heads such as this are designed with revised spark plug locations, and incorporate decks with a minimum thickness of approximately 9/16-inch. This provides ample room to mill the heads (and consequently reduce the chamber volume).
When all is said and done, what's the point? It's simple: When searching for heads for a given Corvette engine combination, think less is more. Sure, big ports equal big flow, but at what cost? No matter what cylinder head you chose, the idea here is to balance the flow with port volume and couple with high-flow velocity. You'll get throttle response, gain torque, and the Corvette will most likely be a whole bunch more fun to drive. It works for us. CF
| FLOW NUMBERS FOR THE BRODIX-HVH OVAL PORT BIG-BLOCK CHEVY HEAD |
| VALVE LIFT (INCH): | .200 | .300 | .400 | .500 | .600 | .700 | .800 |
| INTAKE FLOW: | 170 | 250 | 307 | 347 | 373 | 384 | 388 |
| EXHAUST FLOW: | 126 | 177 | 212 | 246 | 267 | 279 | 288 |
| (Flow CFM at 28 inches) |