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ls6 or 5.3?

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Old 01-24-2010, 11:56 PM
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Default ls6 or 5.3?

going with a 228r with prds, dual springs, lifter, timing chain, and ported oil pump. my issue is picking heads. i was leaning towrds the 5.3's to get a little better compression but have heard some people who didnt like them due to not enough airflow. is the the 228 small enough for these heads or is there a better option? its a 2000 ls1 m6. looking for the 420-440 ish range hp wise but isnt my biggest concern. other mods are in sig...rear end and clutch coming too!
Old 01-25-2010, 02:37 AM
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lol, we almost have the same problem. I am also going to get a H/C package from tsp but i cant decide on a cam, either the 228r or the torquer v2. I do think I am going to go with the 5.3 heads though. After doing some research, alot of people say go with the 5.3 if your running a ms3 cam or smaller and go with the ls6 if your running a ms4 cam or bigger. dont know if that helped or not.
Old 01-26-2010, 12:34 AM
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yea it did. ive been leaning towards those anyways. good price and most people that have them like them. i figured they would be ok though considering the 228 isnt the biggest cam by any stretch.
Old 01-26-2010, 10:05 AM
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yeah, I think im going to go with the 228r and the 5.3s.... i think with this cam, the better compression would be better then the higher flowing ls6 heads which is better suited for bigger cams.
Old 01-26-2010, 01:01 PM
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yeah i think the compression is what sold me. someone else on here had i think the same set up pretty much plus whatever his intake and exhaust setup was. he was around 425 hp i wanna say. hopefully ill be round that. nkow anywhere i can get a rear end that wont cost me a fortune?
Old 01-26-2010, 01:09 PM
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I'm pretty sure Texas Speed would mill the LS6 heads to your specs, so I don't think the compression argument is valid.
Old 01-26-2010, 01:34 PM
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true. although i dont think i would want the ls6 heads because it would tempt me to go with a bigger cam. im doing a rebuild n only looking to hit around 400-425 hp. pretty much a weekend- nice weather cruise car with sparse track time. sorry to jack my own thread but never had a rebuild done before. im assuming my block will be pretty much ok. spun a bearing. planning on replacing the rotating assembly too so all parts combined im around 4k $. would i be able to get everything done for about 6-6500k? im hoping it wont be too much more. i wish i could do the labor myself but i dont have the space or tools n dont trust anyone i know around here to do it.
Old 01-26-2010, 01:38 PM
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im going to get 5.3 stage 2.5 head , by doing alot of search i have seen more people run 5.3 heads with the tv2 cam hitting low 11s than ls6 heads. that is my go with the mods in my signature plus they are cheaper in price
Old 01-26-2010, 01:41 PM
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LS6 heads EVERY time......
Old 01-26-2010, 01:48 PM
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yeah ive heard pretty much 50/50 on this. i think due to the fact that im not really gonna be running in the high rpm's and im not doing a whole lot engine wise after this that the 5.3 are a better choice with the 228. if i wanted to go all out id be going with a 383 with the rebuild n going ***** to the wall
Old 01-26-2010, 01:58 PM
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You could go with this shortblock, get the forged rod upgrade for $500, and get your LS1 heads fully ported with bigger valves.
Lets see, the short with rod upgrade would be $2999.99, the head work without valves would be $1150, so you are up to $4149.99. Let me know if this sounds good to you.
Thanks,
Old 01-26-2010, 02:08 PM
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Originally Posted by 2000RDT/A
true. although i dont think i would want the ls6 heads because it would tempt me to go with a bigger cam.
By far one of the best excuses I have ever heard for not using LS6 243 heads.

The LS6 heads gives you plenty of room to grow and do what ever you want even if you want to stay with a small cam. You can fit the lighter LS6 valves with no issues which over all gives you a very light valve train specially if you are using the stock rockers. I personally would use the Ls6 they bring a hell of a lot to the table even in stock form and by far one of the best flowing heads GM has put out. Why do you think so many guys use the LS6 heads on applications with cars pushing 600+ rwhp.

You can have TEA Texas Speed or AI do a good cam match to the heads and you will not be sorry.


243
Stock Head Flow Numbers
Chamber 64.45 cc-------0.100---0.200--0.300--0.400---0.500---0.550---0.600
Intake 210 cc------------62------126----184----224-----251----256----257
Exhaust 75 cc------------57------108----143----163-----176----180----183
Old 01-26-2010, 02:09 PM
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Back to the original topic...I dont think the 5.3's flow any better than the LS6's anywhere in the rev range, and I doubt velocity is really any different, so I don't really understand what the concern is. In the future a pair of 243's could be taken back off and worked even further, whereas the 5.3's (PRC 2.5's) I believe are pretty much topped out flow wise. Also, 243's are going to hold their resale value if you ever step it up to an aftermarket casting versus the cheap 5.3 casting. I really believe the 243's are where its at as far as STOCK castings go (and also 799's from what I've read, basically same casting). This is my advice/opinions, use what you've compiled to make your choice. Good luck with the build
Old 01-26-2010, 02:56 PM
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well that is why i started a thread. trying to get advice from those who have been there before and know more than me. the above comment i posted was me trying to keep myself from modding this car till it falls apart lol. tho im sure i will anyways-its like a disease...yea im really split heads wise. ive been on here for about a year now reading and reading and going through threads and stickies but heads and cam seems pretty confusing until you've done it i guess. then its a matter of mixing and matching till you get your desired outcome from what i've gathered. thanks to everyone for the info. keep it coming. opinons from both sides of the spectrum are more than welcome!
Old 01-27-2010, 12:25 AM
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Im doing the same setup as you. From all the different dynos on this forum the 5.3s are the way to go. They are perfect for this setup in particular. However the ls6 heads would be good if you wanted me potential.But like you said, if you choose to not mod further down there road the 5.3s sound legit. And several people have dynoed around 420-430rwhp on average with a m6. Hope this helps.
Old 01-27-2010, 12:55 AM
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yeah while i know ill want to do more engine mods im gonna keep it at this and put my money into the suspension and rear end to put it all to use. would i like 500hp ...sure but i dont need it. if i get to around 425-450 with my setup all said n done im sure ill be pretty pleased . and yeah from everything ive seen these heads with the 228r cam are a pretty nice match up- ive seen quite a few people on here with the same heads and cam making decent numbers




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