Configuring a new TSP Long block and looking for advice on heads
04-25-2013, 07:01 PM
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Configuring a new TSP Long block and looking for advice on heads I'm trying to configure a new engine for my 98 Vette. The car has the best RPM transmission and dynotech rear end available, Z06 Ti mufflers, corsa exhaust except stock ceramic coated manifolds, 78mm FAST intake (may need to go bigger).
This is a daily driver car that needs to run on 91 octane but may see the occasional 1/4 mile pass and maybe I'd throw a 150 shot on it once or twice . I want it to have a very tame stockish idle. I care about 1/4 mile mph, not dyno numbers. Anyway I'm pretty well decided on the block: 408 LQ9 (http://texas-speed.com/p-3542-tsp-st...ong-block.aspx) and I am trying to decide between either the 228R or Torquer V2. I know those are relatively small for a 408 but again I am wanting this to not have much lope at all and a stockish idle quality. The dilemma right now is the heads and here is what my concerns are:
1. Compression ratio: What is safe on 91 octane? I'm thinking 10.5:1? I do not want to have any issues with pre-detonation.
2. Pistons: My assumption was that a flat top piston is a better design because it doesn't have the lip of the dish which may cause hot spots. Also I figured the dish may cause less than desirable flow and mixture within the cylinder.
3. Head gaskets: I thought the considerations were mainly to adjust compression ratio but my buddy is telling me something about quench that I have heard of but don't really know anything about. Is thinner better in general?
4. Finally Heads: The long block comes standard with PRC Stage 2.5 LS6 (64cc) or LQ9 (72cc) heads but for more $$ I can get better flowing heads up to some 260cc ones with hollow valve stems. I've never researched heads much but I'm aware of how flow rates at certain lift values works. The question would be: is the head thats gonna get me the fastest trap times the one with the best flow rate. Seems obvious but I'll ask anyway. And the other question is there ever a downside to badder heads? Like bigger cams get you more and more power at the sacrifice of making your car sound lopier and lopier. With heads, at some point do you lose drivability, do they become less effective at some point because of the mild cam, or is bigger always better? Then last question for now, what with hollow stem intake valves? I'll go do some research now but figured I'd ask anyway. Here are the head options I am looking at:
PRC Stage 2.5 LS6 64cc
PRC Stage 2.5 LQ9 72cc
PRC 225cc As-Cast 62-68cc
PRC Stage 2.5 LS3/L92 Hollow-Stem Intake, 64-70cc
PRC 215cc, 62cc
PRC 227cc 60-68cc
PRC 237cc, 68cc
PRC 250cc LS3, Hollow-Stem Intake, 68cc
PRC 255cc LS3, Hollow-Stem Intake, 68cc
PRC 260cc LS3, Hollow-Stem Intake, 68cc
Thanks for any help you can give!
This is a daily driver car that needs to run on 91 octane but may see the occasional 1/4 mile pass and maybe I'd throw a 150 shot on it once or twice . I want it to have a very tame stockish idle. I care about 1/4 mile mph, not dyno numbers. Anyway I'm pretty well decided on the block: 408 LQ9 (http://texas-speed.com/p-3542-tsp-st...ong-block.aspx) and I am trying to decide between either the 228R or Torquer V2. I know those are relatively small for a 408 but again I am wanting this to not have much lope at all and a stockish idle quality. The dilemma right now is the heads and here is what my concerns are:
1. Compression ratio: What is safe on 91 octane? I'm thinking 10.5:1? I do not want to have any issues with pre-detonation.
2. Pistons: My assumption was that a flat top piston is a better design because it doesn't have the lip of the dish which may cause hot spots. Also I figured the dish may cause less than desirable flow and mixture within the cylinder.
3. Head gaskets: I thought the considerations were mainly to adjust compression ratio but my buddy is telling me something about quench that I have heard of but don't really know anything about. Is thinner better in general?
4. Finally Heads: The long block comes standard with PRC Stage 2.5 LS6 (64cc) or LQ9 (72cc) heads but for more $$ I can get better flowing heads up to some 260cc ones with hollow valve stems. I've never researched heads much but I'm aware of how flow rates at certain lift values works. The question would be: is the head thats gonna get me the fastest trap times the one with the best flow rate. Seems obvious but I'll ask anyway. And the other question is there ever a downside to badder heads? Like bigger cams get you more and more power at the sacrifice of making your car sound lopier and lopier. With heads, at some point do you lose drivability, do they become less effective at some point because of the mild cam, or is bigger always better? Then last question for now, what with hollow stem intake valves? I'll go do some research now but figured I'd ask anyway. Here are the head options I am looking at:
PRC Stage 2.5 LS6 64cc
PRC Stage 2.5 LQ9 72cc
PRC 225cc As-Cast 62-68cc
PRC Stage 2.5 LS3/L92 Hollow-Stem Intake, 64-70cc
PRC 215cc, 62cc
PRC 227cc 60-68cc
PRC 237cc, 68cc
PRC 250cc LS3, Hollow-Stem Intake, 68cc
PRC 255cc LS3, Hollow-Stem Intake, 68cc
PRC 260cc LS3, Hollow-Stem Intake, 68cc
Thanks for any help you can give!
Last edited by animuL; 04-25-2013 at 07:10 PM.
04-25-2013, 08:31 PM
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12.0 is good to about 91 octane, how much lift is acceptable for you. FAst intake is good to about 330 cfms stock. PRC 250-255cc LS3, Hollow-Stem Intake, 68cc / PRC 260cc LS3, Hollow-Stem Intake, 68cc if they fit 4.030 bore not sure. I really like TFS ls3 255cc heads. Hollow stem are what they say they are hollow = lighter.Bigger is not always better if you get a 316cc LSX DR head with a large port and your lift is only .600 and I get TFS LS3 with 255cc your heads flow roughly over.400 at .700 lift and TFS flows 382 at .700 lift I'm going to win because of velocity and not using heads for overall goal.Like bigger cams get you more and more power at the sacrifice of making your car sound lopier and lopier.Thats not true of cams the lopy sound is your headers and LSA of the cam 120 lsa is a production car and 110 lsa sounds lopier.Heads don't,lose drivability,it's the cam.
Last edited by lil john; 02-01-2015 at 02:26 PM.
04-25-2013, 09:23 PM
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118 lsa is for something like stock Camaro or stoc anything. I would get PRC 250 - 255cc and a Fast intake with 102 throttle body ported if you got the $$$$$.Fast intake Limit's flow at . 600 to .700 lift. For the intake try to match intake flow to heads it would be useless to have heads that flow .390 cfms at .650 and the intake flow only to ..330 cfms at .650 lift, does this make sense, pick heads to match intake. PRC 250 - 255 heads don't flow to much different but Fast (although it's a great intake it will lose flow at .600 or above if you have the $$$$ get it ported to get the maximum CFM's to match the heads.
02-01-2015, 01:44 PM
#6
I would go with some sort of a ls3 head depending on budget will depend if it's a aftermarket casting or not. A stock ls3 intake does pretty damn well and a 90mm tb. The ls3 heads also do very well with smallish camshafts.
