{"id":23621,"date":"2016-02-09T06:13:47","date_gmt":"2016-02-09T14:13:47","guid":{"rendered":"http:\/\/www.racingjunk.com\/news\/?p=23621"},"modified":"2016-11-30T13:52:28","modified_gmt":"2016-11-30T21:52:28","slug":"brodix-heads-part-ii","status":"publish","type":"post","link":"https:\/\/www.racingjunk.com\/news\/brodix-heads-part-ii\/","title":{"rendered":"Brodix Heads – Part II"},"content":{"rendered":"

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

Last issue<\/a> we examined the intake side of Brodix\u2019s latest BR 7 series of cylinder heads (designed to fit Chevy\u2019s LS-series engines).\u00a0 From the intake perspective, the BR7\u2019s are over the top when it comes to air flow capabilities \u2013 so much so that they pretty much eclipse all original Chevrolet big block production line castings.\u00a0 The reality is, they\u2019re better than many very, very good aftermarket big block heads too.<\/p>\n

When it came to the heads, something was nagging away.\u00a0 And that something was the exhaust port.\u00a0 Now, for an older hot rodders, it\u2019s not hard to forget Ford\u2019s first 351 Cleveland and Boss 302 motors. Way back when (in the late sixties and early seventies), it was no secret that the intake port was pretty much awesome, at least for the time.\u00a0 The exhaust port on those things, on the other hand wasn\u2019t exactly great.\u00a0 The intake\/exhaust ratios were way off too.\u00a0 Here\u2019s a look at the flow numbers of a 4 barrel 351 Cleveland head (2.19-inch intake; 1.71-inch exhaust):<\/p>\n

 <\/p>\n

Ford 4V Cleveland<\/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 131\u00a0\u00a0\u00a0 188\u00a0\u00a0\u00a0 220\u00a0\u00a0\u00a0 256\u00a0\u00a0\u00a0 269\u00a0\u00a0\u00a0 279<\/p>\n

Exhaust Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0 88\u00a0\u00a0\u00a0\u00a0 129\u00a0\u00a0\u00a0 146\u00a0\u00a0\u00a0 159\u00a0\u00a0\u00a0\u00a0 165\u00a0\u00a0\u00a0 166<\/p>\n

 <\/p>\n

The racer\u2019s solution to the under-performing exhaust port was straightforward and to the point:\u00a0 The exhaust side of the head was machined right off and a plate was screwed onto the head, effectively raising the exhaust port.\u00a0 It was something you could get away with on a drag race only engine, but certainly not something you could live with on the street. So is the Brodix BR head in that league?<\/p>\n

We\u2019ll find out in a minute, but using the same parameters for comparison as we did in the first article, let\u2019s examine the flow data on various known Chevy heads (flow data in cubic feet per minute (CFM) using a baseline figure of 28-inches of water for comparison purposes):<\/p>\n

 <\/p>\n

Chevy Small Block 492 w\/1.60-inch exhaust 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

Exhaust Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 107\u00a0\u00a0\u00a0\u00a0 125\u00a0\u00a0\u00a0 137\u00a0\u00a0\u00a0 141\u00a0\u00a0\u00a0 141\u00a0\u00a0\u00a0 141<\/p>\n

 <\/p>\n

Chevy Big Block 290 with 1.72-inch exhaust 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

Exhaust Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 90\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 118\u00a0\u00a0\u00a0 138\u00a0\u00a0\u00a0 160\u00a0\u00a0\u00a0 174\u00a0\u00a0\u00a0 184<\/p>\n

 <\/p>\n

Chevy Big Block 291 with 1.72-inch exhaust 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

Exhaust Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 112\u00a0\u00a0\u00a0\u00a0 139\u00a0\u00a0\u00a0 163\u00a0\u00a0\u00a0 180\u00a0\u00a0\u00a0 194\u00a0\u00a0\u00a0 197<\/p>\n

 <\/p>\n

Chevy Big Block 990 with 1.88-inch exhaust 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

Exhaust Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 106\u00a0\u00a0\u00a0\u00a0 140\u00a0\u00a0\u00a0\u00a0\u00a0 162\u00a0\u00a0\u00a0 181\u00a0\u00a0\u00a0 204\u00a0\u00a0\u00a0 207<\/p>\n

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

So far so good, but how much air does the Brodix BR 7-series cylinder heads move?\u00a0 Here\u2019s a look at figures we collected (again, in CFM using 28-inches of water as the benchmark):<\/p>\n

 <\/p>\n

BR 7 with 1.614-inch exhaust<\/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

Exhaust Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 113\u00a0\u00a0\u00a0\u00a0 158\u00a0\u00a0\u00a0\u00a0 188\u00a0\u00a0\u00a0 208\u00a0\u00a0\u00a0 216\u00a0\u00a0\u00a0 221<\/p>\n

 <\/p>\n

STS BR 7 with 1.614-inch exhaust<\/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

Exhaust Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 116\u00a0\u00a0\u00a0\u00a0 169\u00a0\u00a0\u00a0\u00a0 208\u00a0\u00a0\u00a0 224\u00a0\u00a0\u00a0 233\u00a0\u00a0\u00a0\u00a0 235<\/p>\n

 <\/p>\n

STS BR 273<\/strong> with 1.614-inch exhaust<\/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

Exhaust Flow:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 116\u00a0\u00a0\u00a0\u00a0 169\u00a0\u00a0\u00a0\u00a0 208\u00a0\u00a0\u00a0 224\u00a0\u00a0\u00a0 233\u00a0\u00a0\u00a0\u00a0 235<\/p>\n

 <\/p>\n

As you can see, the exhaust flow on the heads pretty much knocks it right out of the park, but how do they compare to the benchmark CNC ported big block head we discussed in the first segment of this series?\u00a0 Here are the exhaust flow numbers for the Brodix STS RR BB-2 Plus heads (remember, these are the super cool direct replacement heads we mentioned in the past article):<\/p>\n

 <\/p>\n

STS RR BB-2 Plus with 1.88-inch exhaust 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 126\u00a0\u00a0\u00a0 164\u00a0\u00a0\u00a0 201\u00a0\u00a0\u00a0 228\u00a0\u00a0\u00a0 251\u00a0\u00a0\u00a0 267<\/p>\n

 <\/p>\n

As you can see, the rat motor outflows the BR 7 heads from roughly 0.400-inch lift and up, but keep in mind the valve is considerably larger on the big block (1.88-inch versus 1.614-inches). From a flow perspective, it\u2019s pretty tough to beat the new head.\u00a0 And in this case (big flow from relatively small port volumes), that will translate directly into real world performance. There\u2019s a wee bit more to the equation (combustion chambers, deck bolt patterns and top end hardware).\u00a0 We\u2019ll examine some of those items in the next issue.\u00a0 Meanwhile check out the accompanying photos.\u00a0 There\u2019s a lot to think about.<\/p>\n

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

\"Brodix\"<\/a>
Here’s the exhaust port on Brodix’ BR 7 series head. The port is fully CNC-machined, and it’s used on both the STS BR 7 along with the big brother STS BR 273.<\/figcaption><\/figure>\n

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

\"Brodix\"<\/a>
Exhaust ports on the BR 7 series cylinder heads are engineered for use with conventional Chevy LS7 components. That means headers (or manifolds) designed for those combinations are a direct fit. Also, note the streamlined guide (with a bronze insert) shown here.<\/figcaption><\/figure>\n
\"Brodix\"<\/a>
Compare these. On the left is the “benchmark” Brodix STS RR BB-2 Plus big block head with the STS BR 7 on the right. The rat motor head eventually outflows the little BR 7, but not before the valve lift hits 0.500-inch.<\/figcaption><\/figure>\n
\"Brodix\"<\/a>
All Brodix BR 7 heads incoroporate a 1.614-inch diameter exhaust valve. The stems are 8-mm in diameter and they’re 5.230-inches long.<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"

Find out why LS engines are so good in Part II of this series.<\/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":[4011,961,218,4800,992,461,321],"class_list":["post-23621","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-engines","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-68Z","jetpack_sharing_enabled":true,"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/23621","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=23621"}],"version-history":[{"count":4,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/23621\/revisions"}],"predecessor-version":[{"id":23858,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/23621\/revisions\/23858"}],"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=23621"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/categories?post=23621"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/tags?post=23621"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}