lq4 408, ls6 cam, ly2 4.8l truck heads? need help
09-01-2010, 08:38 PM
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lq4 408, ls6 cam, ly2 4.8l truck heads? need help I have a few questions that need answers. I know specs specs for truck cams and for the 01 ls6 and 02+ ls6. Not much difference in duration but a noticeable difference in lift and at what rpm the power comes in. I've heard of 35whp gains from ls6 cam in a 5.3 what should I expect from 75 or so more cubic inches? For my 408 how would both of those cams work out? And for now I'm using my completely stock heads off my 2008 4.8 l truck engine.what would b my limits on lift on my stock valve springs? And any other input or help will b really appreciated. Thanks everyone
09-02-2010, 09:26 AM
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I know I need a bigger cam but I'm trying to just get by right now. I know a bigger cam makes more power. But will I still get some performance out of those cams? I'm not complety sure of my compression yet. The stock lq4 heads had a 70 cc ish combustion chamber and made 9.5 :1 these heads have a 61 CC combustion chamber. And I've got a slight dish on my pistons but I'm not sure how much... I'm thinking somewhere around 11 ish for compression, but just a guess
09-02-2010, 09:34 AM
#5
I know I need a bigger cam but I'm trying to just get by right now. I know a bigger cam makes more power. But will I still get some performance out of those cams? I'm not complety sure of my compression yet. The stock lq4 heads had a 70 cc ish combustion chamber and made 9.5 :1 these heads have a 61 CC combustion chamber. And I've got a slight dish on my pistons but I'm not sure how much... I'm thinking somewhere around 11 ish for compression, but just a guess
I am pulling my 230/234 .612/.598 cam out of my old 346 tomorrow or this weekend at the latest. If it checks out good (I expect it to) it is up for $200. That would be a torquey MF in a 408......
09-02-2010, 09:46 AM
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Yes it would lol! But for right now I'm sticking with a stock converter in my automatic. And really was gonna pick a cam that wouldn't go past my stock valve springs limit. And I don't know what That limit is. If I could find a way to get that cam, and new valve springs and retainers for a good deal then maybe. But all the cam kits I'm finding are all over 850 bucks!
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09-02-2010, 10:44 AM
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This engine is goin in a daily driven silverado short wheel base single cab. So I'm building it totally crazy yet. Still have streetability. If I need more on the track I got my slicks and nitrous. Went with the larger 408 for easy horespower without throwing a massive cam or doin crazy compression or major headwork. Don't get me wrong lol if I could afford all that it already be on it! Ha! That's y I'm reusing the truck heads. Need to know what my Max lift on Those springs are.. and using a stock cam swap from something else to stay on the cheap and pick up however much power I can with staying within pretty much stock parts. So any help with this will really b appriciated thanks everyone
09-02-2010, 02:20 PM
#11
If you decide you want to port the 4.8/5.3 heads let me know we offer cnc porting of customers cores for very reasonable $$$
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Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
09-02-2010, 05:12 PM
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Would the 117 lobe separation on the ls6 cam move my power band to much for my truck? I would figure I would need good low and midrange power cause its a truck. Would that be an ok lob Sep?
It will be fun in that truck for sure
09-02-2010, 11:48 PM
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I have a few questions that need answers. I know specs specs for truck cams and for the 01 ls6 and 02+ ls6. Not much difference in duration but a noticeable difference in lift and at what rpm the power comes in. I've heard of 35whp gains from ls6 cam in a 5.3 what should I expect from 75 or so more cubic inches? For my 408 how would both of those cams work out? And for now I'm using my completely stock heads off my 2008 4.8 l truck engine.what would b my limits on lift on my stock valve springs? And any other input or help will b really appreciated. Thanks everyone
09-03-2010, 07:51 AM
#18
I calculated the SCR. With guesses at a couple of things, here is what I have...
Cylinder Head Volume: 61cc
Piston Head Volume: -8cc
Gasket Thickness: 0.052"
Gasket Bore: 4.030"
Cylinder Bore: 4.030"
Deck Clearance: -0.010"
Stroke: 4.000"
SCR: 11.755:1
Cylinder Head Volume: 61cc
Piston Head Volume: -8cc
Gasket Thickness: 0.052"
Gasket Bore: 4.030"
Cylinder Bore: 4.030"
Deck Clearance: -0.010"
Stroke: 4.000"
SCR: 11.755:1
09-03-2010, 09:32 AM
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I don't have the 6.0 heads. And 11.5 to 11.75 is doable. What about a custom grind cam? I could get Exactly What I need but Idk how much Those cost or where to go to get it.
09-03-2010, 12:00 PM
#20
Thats 11.75 with -8cc dish pistons, 0.010 out of the hole, stock thickness gasket, and that could greatly change with any of those values. With -3cc pistons and a 0.040" gasket, its at 12.9:1 so make sure get all of those specs before you do anything further...