{"id":23631,"date":"2016-02-16T06:22:18","date_gmt":"2016-02-16T14:22:18","guid":{"rendered":"http:\/\/www.racingjunk.com\/news\/?p=23631"},"modified":"2016-11-30T13:51:19","modified_gmt":"2016-11-30T21:51:19","slug":"brodix-heads-part-iii","status":"publish","type":"post","link":"https:\/\/www.racingjunk.com\/news\/brodix-heads-part-iii\/","title":{"rendered":"Brodix Heads – Part III"},"content":{"rendered":"

\"Brodix\"<\/a><\/p>\n

Over the past couple of issues (Part I<\/a>, Part II<\/a>) we\u2019ve taken an overall look at the why LS engines are so good \u2013 with a focus on cylinder heads. If you recall, we used a good set of aftermarket heads (Brodix BR7 jobs) as examples.\u00a0 In the first pair of articles, we looked at both the intake and exhaust ports on those cylinder heads. Both flow prodigious quantities of air through relatively small ports.\u00a0 It\u2019s no secret that makes for a pretty darned good head.\u00a0 But there\u2019s a wee bit more to the equation \u2013 great heads need an equally great combustion chamber. They also need a solid valve train layout.\u00a0 And that\u2019s the basis for this final chapter in our series.<\/p>\n

First, let\u2019s look at the combustion chamber:\u00a0 Traditional Chevy small block cylinder heads have a valve inclination angle of 23-degrees.\u00a0 Stock style big blocks are splayed, but the intake valve angle is actually \u201cworse\u201d at 26-degrees. Admittedly, it\u2019s canted 4-degrees, while the exhaust valve angle is 17-degrees with a similar 4-degree cant.\u00a0 In either case, if the valve angle is flattened (for example, small blocks to 18-degrees, big block intakes to 24-degrees), airflow is improved, and so is the combustion process because the \u201cstraightening\u201d helps to unshroud the valves.\u00a0 Where the Chevy LS motor really differs is the valve angle. In the case of the Brodix BR 7 series of cylinder head, the valve angle is 12-degrees. Essentially, that straightens the valve up, unshrouds the sides of the valves within the combustion chamber and provides the basis for a small, efficient chamber.\u00a0 That translates into a situation where you can move air at a faster pace (increase velocity), and that\u2019s really good news when it comes to cylinder heads.<\/p>\n

In case you\u2019re wondering, the first generation LS motor with a cathedral style port had the valves inclined at 15-degrees. Ditto with later LS3 and L92 style heads. The LS7 Corvette motor was the first with 12-degree heads (although the C5R race head, which preceded it is actually an 11-degree valve inclination affair). Essentially, Brodix took the basic valve layout of the Chevy LS7 head and enhanced it. In the case of the Brodix heads, the bowls on the basic BR 7 have been blended. On the STS BR 7, the chambers are completely machined (see the photos for a closer look). Ditto with the take-no-prisoners STS BR 7 273.\u00a0 In terms of head bolts, the BR 7 series accepts five or six head bolts per cylinder (standard LS7 or LSX).\u00a0 They take a readily available gasket from Fel Pro (1185-041) or GM (12582179), which is a stock Chevy LS7 head gasket.\u00a0 Spark plugs are conventional 14-mm jobs with \u00be-inch reach (gasketed).\u00a0 More gasket specifications along with spark plug recommendations are shown in the accompanying technical specifications sidebar.<\/p>\n

In terms of chamber volume, the Brodix BR 7\u2019s are pretty much the same as all other LS7 style heads \u2013 they measure 71-cc\u2019s.\u00a0 They can be milled to reduce chamber size, but given the already reasonably small chamber, it\u2019s probably sufficiently sized for 99% of all applications.\u00a0 One thing you should be aware of is the fact these heads must be used on engines with bore sizes no smaller than 4.125-inches. Otherwise, you\u2019ll end up with a valve kissing a cylinder wall.<\/p>\n

Topside, the Brodix BR 7 heads are designed to use all stock components. That means conventional Chevy LS7 valve train hardware, or aftermarket hardware for the LS7 can be used.\u00a0 When you specify assembled heads, springs, retainers and locks can be custom tailored to your application. For example, the heads in the photos are fitted with titanium retainers and springs with 430 pounds open pressure (185 pounds on the seat). They\u2019re good for a 0.700-inch lift mechanical roller camshaft. \u00a0Brodix has recently upped the ante with a \u201cBig Spring\u201d version of this head. It accepts springs up to .650-inch in diameter.<\/p>\n

The heads can be setup with conventional LS7 rocker pedestals to accept the offset intake rocker used on the LS7, but they can also mill the pedestal bosses flat. This allows you to use an aftermarket shaft rocker arrangement (Jesel, Crower and T&D all offer rockers for this arrangement).<\/p>\n

What about accessories?\u00a0 All of the BR 7 heads have their ends milled and drilled to accept all common LS-motor accessories. That means any of the common accessory drive brackets bolt right on. Up top, the valve cover rail is in the stock location. Brodix also copied the stock valve cover pattern. That means stock Chevy (or aftermarket pieces for a stock Chevy) bolt right up.<\/p>\n

Whew.\u00a0 As you might have guessed from going over this article along with the pair of earlier ones, the new aftermarket LS heads are pretty much over-the-top in terms of features and performance capability.\u00a0 Not only do they provide considerable performance potential, the overall packaging of the heads allows direct fits to many different race applications (production line and custom). But the bare bones reality (for me too) is that technology has finally caught up and has surpassed the well-established Chevy performance benchmarks.\u00a0 The LS engine is definitely where it\u2019s at in terms of performance, and Brodix\u2019s BR 7 series of heads are an excellent example of what is available today.\u00a0 Today\u2019s technology really is in the fast lane.<\/p>\n

BR 7 Technical Specifications<\/strong><\/p>\n

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