fast01

iTrader: (16)

I've got an LS6 long block in my car with bone stock 243's (obviously). Would it be worth it to swap them for a set of CNC'd 853/241's with 2.02/1.57 valves, .650 lift springs and titanium retainers? Here's the #'s:

Lift Intake Flow C.F.M
Exhaust Flow C.F.M

.100" 67 61
.200" 133 108
.300" 194 147
.400" 242 183
.500" 274 205
.550" 290 213
.600" 296 220

Oh yeah, I'll probably do a cam too!

rocksws6

iTrader: (4)

Why not have your existing 243's worked? You would come out better like that. The P/P would be an improvement over the non-ported 243's but if you were to have the 243's P/P they would be a better choice than the 241's. Just something to think about if you haven't already.

93redBIRDman

iTrader: (9)

you would not come out any better porting 243's over 853/241's. They all come out to about the same, depending on who does the CNC/porting work. And yes you will pick up some good power going with PORTED 853/241's over STOCK 243's...

fast01

iTrader: (16)

I kinda figured I'd get opinions on both sides of the fence! Basically, I just neede someone to agree with me on swapping out the 243's. It's easier to justify it to myself that way. Besides, I'm getting a deal that's real hard for me to pass up!

1999ssls1

iTrader: (71)

Did you ever install that hotcam I sold you?

Evans752

iTrader: (29)

I wouldnt change them out, I would keep my 243 because they up the compression and compression is Horsepower and the way the 243 heads compustion champer is designed makes them what they are. Ported heads are only worth 20 to 30 horsepower but going from stock LS1 241 to 243 LS6s is worth that to.

fast01

iTrader: (16)

No, no Hotcam yet! I'm gonna do heads at the same time. I've actually got 2 engines I'm working on. One for my '71 Camaro and one for my '01. I haven't decided which car will get the Hotcam yet.

As far as compression goes, you are right; compression is power! I just don't know what's worth more, 1/2 pt. in compression or 20-30 cfm flow.

93redBIRDman

iTrader: (9)

I could have sworn I've read somewhere on here that 243's actually lower compression, but someone please correct me if I'm wrong. But also please site where you're getting your info

WS6Drop

iTrader: (10)

If your worried about compression, go with a thinner headgasket. Ported 241's/853's will make more power. You will also have all the hardware on the heads already for your new cam. Just watch PTV clearence.

Shawn @ VA Speed

iTrader: (3)

with the right cam you can make as much power with stock 243's as you can with ported 241's,we have made 440rwhp with bone stock 243's with a nice custom cam.

93redBIRDman

iTrader: (9)

You honestly think STOCK 243's will perform just as well as nicely PORTED 853/241's??????? Am I missing something here???

Of course you CAN make good power with stock 243's, they're good heads, but lets be honest here, nicely PORTED 853/241's will make more power every time...

Shawn @ VA Speed

iTrader: (3)

not enough to warrant spending the money on them when he has the 243's,how many ported 241's on stock bottom ends with a cam in the low 230's make over 440rwhp?

99mongooSS

iTrader: (4)

keep the 243's

93redBIRDman

iTrader: (9)

Well that depends on how much money he's willing to spend, but yea if he's on a tight budget, then stick with the stock 243's and you can still make good power. I believe Patriot will CNC port 853/241's for only like $400. That's cheap horsepower if you ask me... For $400 they'll flow over 290cfm I believe...

Also, the second part of your statement makes it sound like you actually believe STOCK 243's will actually make MORE power than nicely PORTED 853/241's... Am I missing something here, because that is rediculous...

dab2pds

not exactly apples to apples comparison, but i picked up .2 and 2+ mph going from ported and milled 241's from lpe (57cc) to ported patriot 243 stage II (59cc), with track conditions virtually identical and no tuning changes. never did run stock 243's though.
Dave

Shawn @ VA Speed

iTrader: (3)

Man i'm not trying to be rude,but you dont even know the combustion chamber sizes of the 243's vs the 241's if you think 243's are going to lower compression ratio.Power to me means more than peak hp,im talking about tq and hp under the curve-average power,what good does it do you to gain 10hp at 6500 rpm's if you lose 20 everywhere else-how long are you at 6500 rpm's,not only that those big heads only work with big cams,if you want nice streetable hp the 243's are the way to go.you dont even know what cam he is going to use,that 290cfm at .600 lift doesnt do any good if he only runs a .550 lift cam,you need to look at other things than peak flow.There is more to making power than big heads and cam-it's called a good combination.

93redBIRDman

iTrader: (9)

The problem is you assume I think all of these things, and that's not true. You mentioned that I think that 243's will lower compression. I said that I thought I had read that somewhere, not that I was some Head Expert and I was stating fact. I even said please someone correct me if I'm wrong, so that tells you right there I wasnt sure about what I was saying...

I know peak numbers don't mean everything, I've been in the LT1/LS1 game long enough. But are you telling me that his STOCK LS6 long block will not pick up ANY mph or ET from going to nicely ported 853's or 241's?? Maybe we should just agree to disagree LOL

fast01

iTrader: (16)

Wow! I didn't mean to start a war over this, I was just looking for some opinions. I know that the 243's have a smaller chamber, hence higher compression, the lightweight valves are advantageous and I believe the overall casting is better, but flow #'s are flow #'s. I just wanted to get some other thoughts on this because I came across a set of the p/p LS1 heads for around the price that was posted earlier to get the 243's cnc'd and I wouldn't have the down time.

93redBIRDman

iTrader: (9)

So it's Ported LS1 heads or stock LS6 heads, those are your two options.

Am I the only one here that thinks this is a no brainer?? Why arent others posting their thoughts, I want to hear more opinions...

mike#9

iTrader: (3)

A set of ported 241's from any reputable shop WILL (no if and or buts about it) make more power everywhere compared to a set of stock 243's.....period. Assuming that intake/exhaust valves are changed, combustion chambers are worked on....yada yada yada. Not a chance in hell that a stock 243 will make the same numbers anywhere in the curve.