tjb406

iTrader: (4)

about how much difference is there in ls3 cnc v/s ls3 non cnc heads? going on 408 with flat tops and comp cam with 231 247 @.050 and .617 .624 lift

Che70velle

iTrader: (6)

Are you asking about flow data, or pricing? Either one really depends on who's program the heads are cut on. Consequently the increase is substantial for both also. Unless your building a race engine, I personally wouldn't bother, as the ls3 heads flow pretty well in stock form, and its hard to justify the price of a CNC head on a daily driver.

Zfan

I have read that the as cast stock heads flow near 330 cfm, not too shabby for untouched castings.

Tainted

iTrader: (9)

Just have the exhaust and bowl area done. The intake side flows stupid good for a stock head but the runner is already big enough, maling it even larger may hurt your low end.

tjb406

iTrader: (4)

was refering to power or flow data. i can easily find price data.its not a daily driver but will see street time. going in a 81 camaro with a 4l80e 3.73 gears will also retain the fuel injection ,but havent decided on stock style or carb style throttle body.

WKMCD

iTrader: (2)

Assuming a composite intake. With that cam...not much difference. With the appropriate cam...15-30HP depending on everything else being correct.

Horrible cam for these heads. Been there-done that.

Dyno Junkie

I'm surprised that you say that is not a good cam?
I think Comp Cams recommends that grind for rectangle port heads.

twinturbo2

iTrader: (16)

what lsA

WKMCD

iTrader: (2)

Maybe for a rectangular port LS7 head. I will only speak to a very similar cam I tried early on. It was a dog and almost impossible to tune for good drivability.

weldermike27408

Ive heard the LS3 heads dont like a lot of duration ... isn't 4.00" bore kinda small for them too

redtan

iTrader: (5)

They like more duration on the exhaust side due to the poor flow compared to the intake side, but not that much split.

It's the minimum required, but it will work.

tjb406

iTrader: (4)

intake center line 109 lobe sep is 113. its the comp cam 281lrr hr-113. it was recomended for the rectangle port heads, thats y i chose it.

A.R. Shale Targa

iTrader: (2)

The stock LS3 heads have a poor EX. to IN. flow ratio and usually need 12-16
degrees more cam timing on the exhaust side. The CNC versions tend to get
that ratio in the 70-75 % in which case you wouldn't need nearly as much
split. Texas Speed, EPS, or Tick can get you dialed in on the right numbers
for what you want the engine to behave like.

Tainted

iTrader: (9)

Thats a pretty huge split. I see folks like pat g and tony saying more than 12* split is hurting more than helping most of the time.

Dyno Junkie

I thought that was the cam you where referring to.

In our cam only LS3 I went with 231 239 .617 .624 113, it's a very "torque" cam with great mid range.

87silverbullet

iTrader: (11)

If that's true, then they are contradicting what Geoff@EPS has on his site.

http://www.engpwrsys.com/index.php?act=viewCat&catId=19

1989GTA

"In our cam only LS3 I went with 231 239 .617 .624 113, it's a very "torque" cam with great mid range."

That is darn close to my TSP VVT-3 camshaft going on my L92. Good news on the torque.

tjb406

iTrader: (4)

i hope it is as good as 1989gta states. i have always been in big and small block chevys before this is my first ls style engine. hoping for good results.

WKMCD

iTrader: (2)

I've run 5 or 6 cams with l92 heads going back to 2006. 18, 10, 8, 6 degrees split. The 18 was by far the worst. The 6 was very good, the 10 was a little better but also a little different. I run 8 degrees now and it's excellent in the 427. Only the 6 degree 234-240 112 +0 was conventional XE-R lobes and it was a very good all around cam. I ran ICL's at 109, 110, 111 and 112. People - 2C5S - have made very good power with as little as 2 degrees. I still think keeping the ICL in that range is where it should be. Keeping CR reasonable so you can run 28 degrees of timing is critical to making power. For me that was 11:3 - 11:4 with 93 octane.

Just my $.03 but do whatever...