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iTrader: (30)

well i just bought a brand new LQ4 crate motor im goin to be putting it in my rcsb 1500 2wd the truck has 4.10s yank ss3600 fully built 60e. so i talked to comp cams and TSP the other day about what cam i should run. i told them what my plans are with the truck comp cams said LSR grind part 54-457-11 heres the specs.

223/231 @50
610/617 lift
112 lsa

TSP told me that i should run the torquer V.3 cam heres the specs

231/234 @50
643/598 lift
111 lsa

i also am goin to be running a set of PRC 2.5 5.3 heads id like to get 11.1 compression outta the motor the heads are 61.5cc im goin to have them milled to 59cc what would my comp be with a .040 mls headgasket.

skeet

iTrader: (18)

what intake you plan on running? what headers you plan on using? as to exhaust pipe size will determine what cam would be nice for the overall setup. why not some bad *** 243 heads?

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iTrader: (30)

right now i have 1 3/4 longtube headers with 2.5 true dual exhaust with a x-pipe no cats magnaflow mufflers. i plan on running the stock truck intake for now but later on im goin to do a fast LSXRT. as far as the heads id like to run those because IMO you cant beat the price and theres plenty of them that make damn good power over on TECH but im open to any other ideas on heads.

skeet

iTrader: (18)

243s will out perform 2.5 5.3 heads any day, get them in the right hands and there one of the best flowing heads out there, specially for a oem casting, drop the 2.5 exhaust go 3" the headers will work fine, once youre dead set on the FAST intake ( which i'll never be but thats my opinion ) then find someone with good cam software and have all the flow data from heads, to intake and exhaust size, then get a cam to match it all, turn the rpms up to around 6800-7000 and you'll be surprised where you end up at on the ETs, not a fan of the truck intake, so you might not have to turn it up as high on the rpms.


i ran the prc heads on my 6.0 yes they are ok for the price, but i just wanted more just wasnt happy with ok i guess lol

if you like i can ask my builder what his cost is on some cnced ported 243s bare? maybe for some comparison? might fit your budget?


just throwing it out there friend, dont know your budget nor do i know what youre wanting to accomplish

OneQwikSS

iTrader: (8)

i second the 243 heads but as far as intake IMO i'd go with a ported LS6 for your best bang for your buck....just my .02

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iTrader: (30)

its funny cause the PRC 2.5 5.3 heads flow 312 in 223 ex at 600 lift and the PRC 2.5 ls6 heads flow 316 in 226 ex at 600 lift is there really a need to go with the ls6 heads over the 5.3 heads cause they flow almost the same.

as far as what im trying to accomplish with this build i want a nice street strip setup that puts down around 400 rwhp nothing to crazy.

skeet

iTrader: (18)

its been awhile so i did some searching, and reread your post again lol being on a lq4 ( my mind set on lq9s ) but besides the point youre still on stock cubed size motor. with this said and saving a $ then yes i can see the 2.5s working for you.. i found this post on tech and it explains alot and found it very interesting, basically for what you have the ls6 heads would be actually to much head for what you have, BUT i was told this also with the ls3 heads that i run, personally i didnt listen reguardless where it came from, and if the numbers its proved to work well even with stock cubes


Originally Posted by cdoggy81
I would go with the 59cc LS6 & here is why...
For a long time I WOULD HAVE voted for the 5.3 heads on a street car. Mainly for what all you read about with their smaller runners & higher compression making more torque & power "under the curve". This is true to a degree. Now since then I have had some LONG talks with major head porters. The keys are runner design, runner volume, flow, velocity, & how they all work together. With stock cubes, you don't want to just start hogging out the intake and exhaust runners because the velocity will probably slow down even though you'll have great flow numbers! Typically with the bigger runners you lose some velocity which will affect your bottom end and part-throttle response. There seems to be a fine line of flow vs. velocity & good porters know this. Runner shape and the cross section of the port is more important (to a certain point) than just runner volume. A well designed smaller runner can flow better than a larger runner. Now all that being said, volume alone does not always dictate velocity. As long as the cross section is not too big, and has the proper shape, you won't lose velocity... Lets look at LS1 heads, LS6 heads & aftermarket heads.

LS1 head ~ 205cc runner & flows ~ 230cfm
LS6 head ~ 215cc runner & flows ~ 260cfm
PRC 5.3 head ~ 220cc runner & flows ~ 317cfm
PRC LS6 head ~ 230cc runner & flows ~ 316cfm

LS6 head has larger runners & flows more than a LS1 head. OK, based on the above info you prob. think it gives up a lot of velocity & low end b/c of the hogged out runners. Not the case... I makes MORE power b/c it is a better "design" & still keeps the velocity up. How can the aftermarket heads have a smaller runners & flow more??? B/C they are a MUCH better design than the LS6
There is a lot more to it than all this but I wanted to point out a few key points. I am sure I missed a lot & others can fill in the gaps.

"I think where I'm getting confused is when you throw "milling" into the mix. By milling the heads, it helps increase compression even more, hence increasing the velocity of movement of air through the heads (please correct me if I'm wrong on this). Can you guys give me a simple explanation as to how this is accomplished?"

No, by milling the heads you ^ compression which = more torque/power.

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iTrader: (30)

thats a good piece of info right there thanks for sharing it. and BTW im talking about the precision race componets 2.5 5.3 heads not the patroit performance ones.

1slowz71

iTrader: (6)

i have a quick ? , with milling the heads and the thinner head gasket are you planning on fly cutting the piston for either one of those cams ! the reason im asking is im on an lq4 with some mti stage 2e 853's that have been milled about .050 and im going to be running an 228/232 .612/.600 on a 111lsa , some people mentioned tha the valve might hit the piston !

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iTrader: (30)

when i talked to TSP they told me with there torqer V.3 cam and a set of PRC 5.3 heads milled to 59cc that there wouldnt be a problem with PTVC on a LQ4 but id still check it to be certain.