Black2003SS Posted April 10, 2007 Report Share Posted April 10, 2007 (edited) Ok. I want to learn about runner volume and the pluses and minuses of each. For example, I was looking at Dart heads today in my spare time. They have a 205cc and 225cc variation. Obviously you can get the ported and polished etc. I know the "cc" is the volume of the intake runner. I also understand that the size of the combustion chamer has alot to do with estimated compression ratio etc. What situations would you want to go with the larger runner volume, I am sure that it must produce more power, but where? Upper RPM's? I also would like to know if you can put the 225cc on a stock 6.0L or it would be overkill. Can you even put the 225cc on a stock motor? Obviously cam selection comes into play as well. Someone told me that the 225cc heads cant fit a stock bore block...is this true? Also Patriot performance also has different "cc" heads as well. They list a bore specification, does that mean you can't put those heads on any smaller bore? AFR also has the same thing. Would you only use 205's on 6.0L and 225's on a 402, 408, 427 etc? I just want to know this stuff for my own personal knowledge, I'm not thinking of really going this route with my motor right now. Lets maybe get some good info together and do a sticky for heads and the pluses minuses/success failures of each. There aren't that many heads out there like cams and I would imagine a little easier to address than cam preferences. Hell....if we can, lets do a cam sticky to. I'll even put them together (learning process for me is bonus). Edited April 10, 2007 by Black2003SS (see edit history) Quote Link to comment Share on other sites More sharing options...
Black2003SS Posted April 11, 2007 Author Report Share Posted April 11, 2007 Great talk guys! Quote Link to comment Share on other sites More sharing options...
12'SROCK Posted April 11, 2007 Report Share Posted April 11, 2007 its actually much more complicated than that. it all depends on you engine setup, n/a, s/c, high rpm, low rpm, main use of the engine. a small port (any thing under +/-215cc), what they consider a high velocity port, is a good low to mid rpm performer. the bigger ports(215cc+) are for bigger cubic /stroker engines which tend to need more air they are in some cases lazy ports(slow velocity) depends though. remeber that an engine is only a compressor, the faster you get the air in and out the more efficient it will become. Quote Link to comment Share on other sites More sharing options...
Sum 1 Posted April 15, 2007 Report Share Posted April 15, 2007 Smaller heads for smaller bore. I went with AFR 205's because I'm running a stock LQ9 short block and a mild cam; 210/218-.581/.581-116. You see in the dyno sheet below that I'm getting great torque under the power curve and dropping off around 5200. If someone was running a 402 or bigger, they'd need to push more fuel/air and keep making power with the 225's. Quote Link to comment Share on other sites More sharing options...
Black2003SS Posted April 15, 2007 Author Report Share Posted April 15, 2007 Now we are getting somewhere. This is good info. You didnt pick up much out of the hole, but looks good for top end power. What changes did you make to go from the lower results of the baseline run versus the final run with 370whp? I also notice you were in warmer weather with the higher run. Quote Link to comment Share on other sites More sharing options...
Sum 1 Posted April 17, 2007 Report Share Posted April 17, 2007 The 316/341 pull was LT's, exhaust and tuning. The 371/381 pull was Heads, cam, injectors, pulleys, tuning. The power does drop off with the stock intake/tb. Quote Link to comment Share on other sites More sharing options...
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