MID12sSSS Posted June 22, 2012 Report Share Posted June 22, 2012 This is a repost from about a week ago. Didnt get any response so thought id try again. About to order some CNC'd 317 heads with LS6 springs. The heads come assembled with GM 2.00 Intake and 1.55 exhaust valves. For $300 more, they'll include stainless steel 2.05 intake and 1.65 exhaust. So my question is, will i see a big enough gain to justify spending another $300? The heads are going on a Forged 6.0 with a Radix. Quote Link to comment Share on other sites More sharing options...
cadowns Posted June 23, 2012 Report Share Posted June 23, 2012 I would be interested to hear more about the complete build. First thought is about what Cam are you going to use, what lift does it have. If it is over .580" I would not think the LS6 springs and a blower are NOT going to be the best for you. A better set of springs will take you a long ways so as reliability is concerned. Also let us know which Radix you are going with, that will also set what size valves are right for you. CD Quote Link to comment Share on other sites More sharing options...
MID12sSSS Posted June 23, 2012 Author Report Share Posted June 23, 2012 I'm running the GT2-3 cam from lingenfelter because it compliments the 112 Radix. And the LS6 springs are perfect for the GT2-3 (all according to zippy). I have a LQ9 at 10.1:1 with an eagle forged crank, Callies compstar forged h-beams, diamond -2cc flat top pistons with valve reliefs, total seal steel rings, ARP 2000 connecting rod pins, GT2-3 cam, SLP double roller timing set, SLP high pressure oil pump, 317 LQ9 CNC ported heads with LS6 springs, .040 cometic head gaskets, NGK TR6 plugs, Taylor race wires, SLP 160* thermostat, Magnuson Radix supercharger with 2.75in pulley, 90mm J-tube, 90mm vette throttle body with harness converter, Volant ram air kit, snow performance meth injection kit, stainless long tube headers, corsa sport exhaust, C6 Z06 corvette brake kit, E-fans, Zippy tune... Trans has shift kit, servos, and I'm looking into a torque converter. Just running the TB right now. Wanna "beef it up a bit, but not sure what all goes into that. And not sure what gains to expect from the bigger valves. Any help or advice with transmission mods and valve knowledge will be greatly appreciated. Thanks. Quote Link to comment Share on other sites More sharing options...
Cramer Posted June 23, 2012 Report Share Posted June 23, 2012 I would spend the extra and have larger valves put in. But that depends on who's CNC'd heads they are, and the flow numbers from regular valves and the larger valves. Quote Link to comment Share on other sites More sharing options...
MID12sSSS Posted June 23, 2012 Author Report Share Posted June 23, 2012 .100 62.3 .200 131.1 .300 181.5 .400 232.4 .500 278.5 .600 310.3 Thompson performance. Not sure which valves were used during flow test. Quote Link to comment Share on other sites More sharing options...
shadowsniper3006 Posted June 23, 2012 Report Share Posted June 23, 2012 what size bore was used to test those heads and find out valve size. Those are perfectly horrible flow numbers, particularly in the lower lift if tested on our 4" bore Quote Link to comment Share on other sites More sharing options...
MID12sSSS Posted June 23, 2012 Author Report Share Posted June 23, 2012 Oh. So if those numbers are from a 4.0 inch bore, then the heads suck? Haha I don't speak flow numbers so I wasnt sure. I'll try to find out what valve size, bore size, etc was used. Since I'm not familiar with the numbers, I just figure that the stock 317 heads flow great, so CNC'd and bigger valves would make them amazing heads. Hmmm. Quote Link to comment Share on other sites More sharing options...
shadowsniper3006 Posted June 23, 2012 Report Share Posted June 23, 2012 nothing wrong a ported 317 head, but for a ported 317 i would touch that head Quote Link to comment Share on other sites More sharing options...
MID12sSSS Posted June 23, 2012 Author Report Share Posted June 23, 2012 You wouldn't? What numbers am I looking for? Quote Link to comment Share on other sites More sharing options...
shadowsniper3006 Posted June 24, 2012 Report Share Posted June 24, 2012 go around to other web sites like tsp, prc and TEA and look at what they are showing for flow. Again make sure you compare apples to apples with what bore size it was tested on. I think it was hot rod or CHP that did a very good ls head test artical to. http://www.hotrod.com/techarticles/engine/hrdp_1012_ultimate_chevrolet_ls_cylinder_head_test/viewall.html do some readign and you'll get a feel for what the average numbers are for a given head/valve size/runner size i always prefer TEA for ported heads, but do some reading and form your own opinion. Quote Link to comment Share on other sites More sharing options...
MID12sSSS Posted June 24, 2012 Author Report Share Posted June 24, 2012 Thanks a lot. I'll do my research. Bummer to hear those heads are garbage. Was a good deal... Quote Link to comment Share on other sites More sharing options...
MID12sSSS Posted June 24, 2012 Author Report Share Posted June 24, 2012 If you could get the stock LQ9 317 heads, and the Thompson performance CNC'd 317 heads for just a little more cash, what would you choose? Or would you scrap the idea of using either and spend the $2,000+ for some great heads. I was running the stock 317s on my old motor and thought they were great. But like I said, not to knowledgable on flow #s... Stock Thompson 317s Performance CNC'd 317s .100 66 62.3 .200 142 131.1 .300 146 181.5 .400 228 232.4 .500 236 278.5 .600. 240 310.3 Quote Link to comment Share on other sites More sharing options...
Cramer Posted June 24, 2012 Report Share Posted June 24, 2012 You can get some CNC'd PRC heads or some Patriot heads with bigger valves and better springs that flow a lot better for cheaper than the Thompson heads. Just because they are CNC machined doesn't mean they are great. All the big porters, and aftermarket CNC'd heads have their own porting design. TEA is top notch along with AFR, Dart, WCCH etc. The price reflects the time and research put into developing their heads. TSP's PRC heads are very good for the price and with a budget build are hard to beat. Just my .02 and the heads are not something you want to skimp on with this. Quote Link to comment Share on other sites More sharing options...
MID12sSSS Posted June 24, 2012 Author Report Share Posted June 24, 2012 Thanks a lot. Sorry about the last post. Tried to type a table, didn't work out so well. Definitely going to look into TSP heads. Haha just order $3600 in parts from them last week. They aren't done with balancing my rotating assembly yet, so maybe I can have them put some heads in the order before they ship. Quote Link to comment Share on other sites More sharing options...
MID12sSSS Posted June 24, 2012 Author Report Share Posted June 24, 2012 About to pull the trigger on the TSP 6.0L stage 2.5 heads. Any objections? .200-147 .300-209 .400-258 .500-294 .600-316 http://www.texas-speed.com/p-1173-prc-stage-25-60l-cnc-ported-heads.aspx Quote Link to comment Share on other sites More sharing options...
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