{"id":23610,"date":"2016-02-02T06:12:55","date_gmt":"2016-02-02T14:12:55","guid":{"rendered":"http:\/\/www.racingjunk.com\/news\/?p=23610"},"modified":"2016-11-30T13:52:50","modified_gmt":"2016-11-30T21:52:50","slug":"brodix-heads-part-i","status":"publish","type":"post","link":"https:\/\/www.racingjunk.com\/news\/brodix-heads-part-i\/","title":{"rendered":"Brodix Heads – Part I"},"content":{"rendered":"

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

When Chevy’s LS motor made its debut almost two decades ago, there were plenty of doubters. It was the new kid on the block and for one thing, the first ones had goofy looking intake ports – tall and skinny. We hadn’t seen anything like it. But time marches on. After riding in, driving, and owning LS powered cars and trucks, most of us discovered it was pretty clear something good was going on under the hood. Later jobs with bigger ports were even better. Those little LS engines packed a punch. A big\u00a0<\/strong>part of that punch was in the cylinder heads. And that’s the reason for this series. We’ll compare a very good, readily available LS head to some of the original standard bearers from both Chevy and Ford. You might be really surprised at the findings:<\/p>\n

In this writer’s case, I happened to have a set of very (Very) nice CNC ported big block cylinder heads sitting on the workbench. They flowed like gangbusters from their 320 cc intake port. Better still, the heads had stock port locations, which meant all stock Chevy hardware (intake, valve train, headers or exhaust manifolds, front accessories) could bolt right on. Those rat motor heads were simply over-the-top. Then something happened: Brodix sent (for evaluation) a set of their latest LS cylinder heads based upon their take of the newer (larger) LS7 port configuration. The more we looked at the heads, the more we became convinced of the reason the LS really honks is because of the cylinder heads. And even more so when it’s topped with a set of Brodix BR-7-series heads. Believe it or not, they’re over the top in comparison to the big block. Here’s why:<\/p>\n

Intake Ports…<\/strong><\/p>\n

On the intake side of the equation, Brodix’ BR-7 heads are based upon relatively small port volumes (although the port is short – more below) and [extremely] high port flow. That equates to considerable air speed in the port, without choking the engine in the usable RPM \u00a0ranges. sound confusing? Let’s back up a bit: Honestly, it’s pretty simple to get big flow bench flow numbers from an equally big hole (big port) in the head. The trouble is, if you just hog the head out, with no regard for the velocity within the port, the engine will be lazy – extremely lazy. In fact it will likely be a dog when it comes to acceleration. The trick is to maintain a relatively small poart layout and then make it flow copious quantities of air (and fuel). Makes sense, but there’s one tiny (albeit critical) caveat: You can’t make the port volume too small for the intended engine RPM range. If it is, you’ll simply choke the port. That means the engine will run out of steam at a specific RPM (likely well below the actual maximum engine speed or “redline”). As you can see, designing and building heads for street driven cars isn’t quite as easy as it might first look.<\/p>\n

Those are the constraints Brodix was faced with when engineering this new series of cylinder heads (bolt-on, stock type hardware, extremely good flow, small port volume, realistic operating range). It wasn’t (and still isn’t) an easy assignment. As a result of the strict parameters, multiple configurations of LS-7 style heads were conceived. For this issue, we’ll concentrate on the intake port side of the equation. And there’s a lot to concentrate on.<\/p>\n

The basic BR 7 head makes use of a 262 cc intake port. The valves measure 2.204-inches and the valve angle is 12-degrees (which is standard LS7-fare). This head also fits all standard LS7-format intake manifolds.<\/p>\n

Next up is the STS BR 7 (shown in the accompanying photos). This Brodix LS style head is completely CNC ported, but still maintains the same 2.204-inch valve diameter as the basic BR 7 head. The port volume on the intake side measures 264-cc’s and it too has a standard 12-degree valve angle.<\/p>\n

The final BR series head in the Brodix pack is a special STS BR 273 job. It has a 2.250-inch intake valve (same 12-degree valve angle) and a port volume of 273 cc’s.<\/p>\n

Now, when you’re comparing intake port volumes, give this some consideration:<\/p>\n

Conventional Chevy Small Block castings we’re all familiar with are 461, 462, 491, 041 jobs. These castings were used in 1965 327-375 “Fuelie” and also applicable to 1970 350-370 HP LT1 engines\/ The intake port volume measures 165 cc.<\/p>\n

492 small block castings were also common. They later became available as angle-plug, over-the-counter high performance replacement heads (never production line installed). Many consider them to be an improvement over the early 461-462-491 and 041 castings. They have an intake port volume of 157 cc.<\/p>\n

Then take a look at several conventional Chevy Big Block castings 280 & 290. These were used on familiar 1970 closed chamber oval port 454’s along with 1966 427-390 horsepower engines, to name a few. The intake port volume measures 256 cc.<\/p>\n

Next up, consider a Chevy Big Block castin 840, 291, or 858. This head was used on 1970 closed chamber rectangular port 454 Special High Performance engines (1970 LS6). The intake port measures between 326 to 327 cc.<\/p>\n

Take a look at Chevy Big Block casting 074 & 077. These are rectangular port, open chamber aluminum heads found on Chevy’s HD L88 and ZL1 engines. The intake port measures 308 cc’s.<\/p>\n

Finally, Chevy’s 990 casting big block head is a rectangular port, open chamber iron head. It was found on vintage LS7 454 crate motors. The intake ports typically measure 318 ti 320-cc’s. Many consider this to be the best configuration of the conventional HD assembly line style Chevy big block heads.<\/p>\n

As you can see, the Brodix BR 7 head series has an intake port volume that is closer to an oval port rat motor than a small block. There’s a wee hitch in the comparison though: The big block has a long intake tract with a couple of convoluted ports. The LS motor is a symmetrical port arrangement (with all ports being equal). They have direct paths right into the combustion chamber. As a result, the ports tend to be shorter than their big block ancestors.<\/p>\n

So far so good, but just how much “air” do these cylinder heads move in the intake port? What follows is a flow data in cubic feet per minute (CFM) collected from Brodix, using a baseline figure of 28-inches for comparison purposes:<\/p>\n

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

 <\/p>\n

Valve Lift (inch):\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .200\u00a0\u00a0\u00a0 .300\u00a0\u00a0\u00a0 .400\u00a0\u00a0\u00a0 .500\u00a0\u00a0\u00a0 .600\u00a0\u00a0\u00a0 .650<\/p>\n

____________________________________________________<\/p>\n

Intake Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 150\u00a0\u00a0\u00a0 244\u00a0\u00a0\u00a0\u00a0 294\u00a0\u00a0\u00a0 334\u00a0\u00a0\u00a0 360\u00a0\u00a0\u00a0 364<\/p>\n

 <\/p>\n

STS BR 7<\/strong><\/p>\n

 <\/p>\n

Valve Lift (inch):\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .200\u00a0\u00a0\u00a0 .300\u00a0\u00a0\u00a0 .400\u00a0\u00a0\u00a0 .500\u00a0\u00a0\u00a0 .600\u00a0\u00a0\u00a0 .650<\/p>\n

____________________________________________________<\/p>\n

Intake Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 159\u00a0\u00a0\u00a0 240\u00a0\u00a0\u00a0 303\u00a0\u00a0\u00a0 343\u00a0\u00a0\u00a0 369\u00a0\u00a0\u00a0 376<\/p>\n

 <\/p>\n

STS BR 273<\/strong><\/p>\n

 <\/p>\n

Valve Lift (inch):\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .200\u00a0\u00a0\u00a0 .300\u00a0\u00a0\u00a0 .400\u00a0\u00a0\u00a0 .500\u00a0\u00a0\u00a0 .600\u00a0\u00a0\u00a0 .650<\/p>\n

____________________________________________________<\/p>\n

Intake Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 147\u00a0\u00a0\u00a0 233\u00a0\u00a0\u00a0 286\u00a0\u00a0\u00a0 344\u00a0\u00a0\u00a0 381\u00a0\u00a0\u00a0 409<\/p>\n

 <\/p>\n

\u00a0<\/strong><\/p>\n

OK. Those are impressive numbers. But how do they compare with a stock Chevy small block or big block port? We gathered up data on a number of different stock small block and big block engines, using figures known to be reliable. The differences in flow might surprise you:<\/p>\n

 <\/p>\n

Chevy Small Block 492 w\/2.02-inch intake valve<\/strong><\/p>\n

 <\/p>\n

Valve Lift (inch):\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .200\u00a0\u00a0\u00a0 .300\u00a0\u00a0\u00a0 .400\u00a0\u00a0\u00a0 .500\u00a0\u00a0\u00a0 .600\u00a0\u00a0\u00a0 .700<\/p>\n

____________________________________________________<\/p>\n

Intake Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 130\u00a0\u00a0\u00a0 173\u00a0\u00a0\u00a0 198\u00a0\u00a0\u00a0 206\u00a0\u00a0\u00a0 209\u00a0\u00a0\u00a0 209<\/p>\n

 <\/p>\n

Chevy Big Block 290 with 2.06-inch intake valve<\/strong><\/p>\n

 <\/p>\n

Valve Lift (inch):\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .200\u00a0\u00a0\u00a0 .300\u00a0\u00a0\u00a0 .400\u00a0\u00a0\u00a0 .500\u00a0\u00a0\u00a0 .600\u00a0\u00a0\u00a0 .700<\/p>\n

____________________________________________________<\/p>\n

Intake Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 122\u00a0\u00a0\u00a0 172\u00a0\u00a0\u00a0 214\u00a0\u00a0\u00a0 244\u00a0\u00a0\u00a0 257\u00a0\u00a0\u00a0 260<\/p>\n

 <\/p>\n

Chevy Big Block 291 with 2.19-inch intake valve<\/strong><\/p>\n

 <\/p>\n

Valve Lift (inch):\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .200\u00a0\u00a0\u00a0 .300\u00a0\u00a0\u00a0 .400\u00a0\u00a0\u00a0 .500\u00a0\u00a0\u00a0 .600\u00a0\u00a0\u00a0 .700<\/p>\n

____________________________________________________<\/p>\n

Intake Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 137\u00a0\u00a0\u00a0 205\u00a0\u00a0\u00a0 248\u00a0\u00a0\u00a0 287\u00a0\u00a0\u00a0 319\u00a0\u00a0\u00a0 323<\/p>\n

 <\/p>\n

Chevy Big Block 990 with 2.19-inch intake valve<\/strong><\/p>\n

 <\/p>\n

Valve Lift (inch):\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .200\u00a0\u00a0\u00a0 .300\u00a0\u00a0\u00a0 .400\u00a0\u00a0\u00a0 .500\u00a0\u00a0\u00a0 .600\u00a0\u00a0\u00a0 .700<\/p>\n

____________________________________________________<\/p>\n

Intake Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 131\u00a0\u00a0\u00a0\u00a0 202\u00a0\u00a0\u00a0\u00a0 234\u00a0\u00a0\u00a0 282\u00a0\u00a0\u00a0 303\u00a0\u00a0\u00a0 322<\/p>\n

\u00a0<\/strong><\/p>\n

It doesn\u2019t take a rocket scientist to see that the Brodix BR 7 series heads move a ton of air in comparison to a conventional small block. In fact, they move way more air than a good stock big block.\u00a0 But wait!\u00a0 Remember that really (Really) good set of heads we had on my bench?\u00a0 Those are actually Brodix STS RR models with a transposed, CNC-machined BB-2 port.\u00a0 They\u2019re likely one of the best heads available today that you can bolt-on a conventional big block.\u00a0 That means that everything from the intake to the exhaust from a stock Chevy fits (including the valve train and accessories).\u00a0 How well do the 320-cc intake ports flow?\u00a0 Here\u2019s the answer:<\/p>\n

 <\/p>\n

STS RR BB-2 Plus with 2.25-inch intake valve<\/strong><\/p>\n

Valve Lift (inch):\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .200\u00a0\u00a0\u00a0 .300\u00a0\u00a0\u00a0 .400\u00a0\u00a0\u00a0 .500\u00a0\u00a0\u00a0 .600\u00a0\u00a0\u00a0 .700<\/p>\n

____________________________________________________<\/p>\n

Intake Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 162\u00a0\u00a0\u00a0 244\u00a0\u00a0\u00a0 285\u00a0\u00a0\u00a0 328\u00a0\u00a0\u00a0 359\u00a0\u00a0\u00a0 369<\/p>\n

 <\/p>\n

 <\/p>\n

Now compare them directly to the STS BR 7 heads we also had on the work bench:<\/p>\n

 <\/p>\n

STS BR 7<\/strong><\/p>\n

 <\/p>\n

Valve Lift (inch):\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 .200\u00a0\u00a0\u00a0 .300\u00a0\u00a0\u00a0 .400\u00a0\u00a0\u00a0 .500\u00a0\u00a0\u00a0 .600\u00a0\u00a0\u00a0 .650<\/p>\n

____________________________________________________<\/p>\n

Intake Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 159\u00a0\u00a0\u00a0 240\u00a0\u00a0\u00a0 303\u00a0\u00a0\u00a0 343\u00a0\u00a0\u00a0 369\u00a0\u00a0\u00a0 376<\/p>\n

 <\/p>\n

 <\/p>\n

Gulp.\u00a0 That big block doesn\u2019t seem so stout any more (especially when you consider the BR series head has an intake volume of 264 cc\u2019s).\u00a0 That\u2019s one big reason why these cylinder heads can make your head spin! For a closer look at the intake side, see the accompanying photos.\u00a0 Next issue, we\u2019ll look at the exhaust side of the equation.\u00a0 Hang on because they have some surprises too!<\/p>\n

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

\"Brodix\"<\/a>
Brodix’ BR 7 series of cylinder heads are remarkable performance pieces, but likely the most impressive fact is the little rectangular intake port that simply outflows all production line Chevy big blocks.<\/figcaption><\/figure>\n

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

\"Brodix\"<\/a>
Dimensionally, the port is 2.350 X 1.350-inches. It’s engineered to work with all stock Chevy and aftermarket LS7 intake manifolds. Inside the port you can see the bronze guides. Valve stems have a diameter of 8-mm with a stem length of 5.20-inches.<\/figcaption><\/figure>\n
\"Brodix\"<\/a>
This is the aftermarket rat motor head we mentioned: Brodix’ STS RR BB-2 Plus. This head moves a huge amount of air while satisfying the need to use all stock hardware.<\/figcaption><\/figure>\n
\"Brodix\"<\/a>
Compare a BB-2 Intake gasket placed over the BR7 intake port. It’s a good visual of how much smaller the new head is when compared to the older big block.<\/figcaption><\/figure>\n
\"Brodix\"<\/a>
The BR7 intake valve measures 2.204-inches in diameter. That’s larger than Chevy’s Special High Performance and Heavy Duty production line big blocks with 2.19-inch intake valves.<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"

Find out why the LS engine is so good.<\/p>\n<\/div>","protected":false},"author":20,"featured_media":23619,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[3448,5008,17,11,9],"tags":[4011,961,218,4800,69,461,321],"class_list":["post-23610","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-drag-race-101","category-engine","category-guest-column","category-how-tos","category-tech-tips","tag-brodix","tag-drag-race-101","tag-guest-columns","tag-how-tos","tag-ls-engine","tag-tech-tips-2","tag-wayne-scraba"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2016\/02\/featured1.jpg","jetpack_shortlink":"https:\/\/wp.me\/p42YSK-68O","jetpack_sharing_enabled":true,"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/23610","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/users\/20"}],"replies":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/comments?post=23610"}],"version-history":[{"count":2,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/23610\/revisions"}],"predecessor-version":[{"id":23731,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/23610\/revisions\/23731"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/media\/23619"}],"wp:attachment":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/media?parent=23610"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/categories?post=23610"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/tags?post=23610"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}