emeraldlion Posted April 20, 2012 Share Posted April 20, 2012 So after reading through several topics on exhausts and 2-1 especially, I found JohnC recommending that the most appropriate placement of a 2-1 merge collector would be approximately 28-32 inches after exhaust valve. The primaries on my headers seem to have approx. 12 inch runners leaving me about 20 inches of down pipes before the merge. The problem I am seeing is this places my merge right underneath my converter/transpan. I am running a sbc with th350 in the jtr position "all the way back." Was planning on going with flex pipes from collectors 2.25" mandrel bent, running two resonators prior to merge and merging to single 3" back to a single borla xr1 at the back in stockish position. Just want to try and do it right the first time. Thanks for any help Quote Link to comment Share on other sites More sharing options...
Xnke Posted April 20, 2012 Share Posted April 20, 2012 The primary length varies based on the RPM range of the engine in question. I belive John was talking about the L28, if I'm thinking of the correct thread, and so it may be different for the V-8. Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 20, 2012 Author Share Posted April 20, 2012 (edited) That would make more sense. I really hadn't thought it was the l28 I was just reading and thinking 2 into 1. I tried to link to the specific article he linked but the link was dead. Edited April 20, 2012 by emeraldlion Quote Link to comment Share on other sites More sharing options...
johnc Posted April 20, 2012 Share Posted April 20, 2012 Correct. The primary length I mentioned was for engines with a 6 cylinder firing interval (120 degrees). Now, this is completely off the top of my head, but my guess for a 90 degree V8 firing order you will need a length to the final merge of 18.5" to 21.5". If that's too short you might be able to double the numbers. But, again, this is off the top of my head and I haven't finished my second cup of coffee yet. Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 20, 2012 Author Share Posted April 20, 2012 Lol, If that's the case my final merge would be directly underneath the oil pan Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted April 20, 2012 Author Share Posted April 20, 2012 If I double the 21 to 42 that might put me just behind the transpan or right at the driveshaft, definitely a little more palatable. I am probably overthinking this because I don't have a super high performance engine and most likely won't. I really don't have an idea of rpm range unfortunately because I don't know what work was done to the engine. It is a 67 283 casting with 601 power pack heads, no idea on pistons or valves(I would assume stock), and unknown cam that has a significant lope. Edelbrock 500cfm out-of-box, with performer intake manifold, and HEI dist. Quote Link to comment Share on other sites More sharing options...
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