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Can I Get To 450 Hp.


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hey guys, so im wonderin can i make around that number at the flywheel wit some different heads on the truck? im running this cam right now XR275HR...222/224 .566/.568 112LSA, along with the supporting mods. if i change heads what could i except for a gains, i havent done to much research into them cus im a little lost when it comes to heads so if you wanna give me some info and your thoughts that would be great. reccomendations would be greatly appreciated to.

thanks guys alex.

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A front mount will definetly get you there with a good set up. To get all of the potenial out of a turbo you would need to do a diffrent cam. I found a set of l92 heads full p&p and all real nice for 1500, 1800 with correct cam from slp who also make a complete kit. Now if you wana make some real crazy power do the heads and turbo and just rape!

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if your planning on going the boost route id leave the heads be and just use the $$$ for a turbo kit or blower. you could make 450 and more if you wanted with just a bit of boost like 7 psi. with boost the only reason i would really change the heads. is if i were looking to get every bit of power out of the motor. not saying that heads wont give you more power with boost i just think the $$$ could be better spent on supporting mods for a turbo/blower. boost isnt cheap. i have just one receipt thats 9k just for my turbo kit and some other parts to make it work.

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theres a good chance your at or close to 450 at the crank allready. With good heads and that cam(with supporting mods) i'd shoot for 400 at the wheels. With the front shaft off i was told to figure about 23% loss so 400 at the wheels is like around 519(400/.77) at the crank. I made 425 at the rears with a head/cam setup with a little bigger cam. I'm not sure the hp increase of just a tune, as i was too new to dyno back then, but just a tune gained me .5 in the quarter when i was stock, i'm thinking thats about a 50 shot of N20 to get an idea, so with just a tune you may be around 395 at the crank plus your headers and cam. If gm didn't under rate the motor.

Edited by shadowsniper3006 (see edit history)
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i always sound like broken record, but i believe in TEA as a head porter. If you choose to go with a factory head, theres nothing wrong with a stock 317 head ported out to stage 3 and decked to around 68cc. If you can swing a little more, a stage 3 ls6 head is nice for a better chamber and more compression(as long as NA is your goal). If you really want to blow some cash, 225 trick flow heads in a 65cc chamber(or maybe decked to 64-63 for real good NA hp).

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http://www.hotrod.com/techarticles/engine/hrdp_1012_ultimate_chevrolet_ls_cylinder_head_test/index.html

 

i don't really know of articles explaining heads, crap loads on cams though, but this article is a pretty good one for seeing how runner sizes and valves sizes can effect things when chamber size is the same. I look at the runner size vs valve size vs flow numbers vs a good hp test like this one. Just picking head with good high lift numbers isn't good enough, a head that has great numbers through out the whole valve lift is what you want. And if a head posts great flow numbers at .650 lift and your motor will never see that, doesn't help you out. I always looked for the heads that posted great number through out the lift and then looked at valve size. If the flow numbers are equal and one head did it with a smaller valve, thats the head i would look at. A smaller valve(with great flow numbers) can give you better valve control, more piston to valve clearance, and better flow into our small stock bore. Also, when first looking at flow numbers, pay attention to runner size. If one head flows 330 with a 245 runner and one head does it with a 225 runner, i would start to look at the 225 head. Based on this article(and words from a wise man) and they're follow up article, it seems to be really hard to over head one of these motors, so i wouldn't fear a 225 or even a 235 runner on a head. Even the ls3 heads seem to make more power and torque at every point(including low end) as the runners get bigger and bigger, it kinda defies everything i thought i knew. If i could get enough piston to valve clearance with the 235 trick flow head(the 235 has a larger valve then the 225 head i have on now) i would have that one on a stock cube motor in a heart beat......but i would lessen my cam as well and let the heads do the work. And with a smaller cam/large head motor I think it would make about the same power but be more street-able and shift lower, but thats just a theory i have from doing some talking with a couple guys.

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