Cobra4B

iTrader: (9)

I recently acquired a 2003 vert and got to thinking about this. The only difference between the two motors is the heads, valves, springs, and camshaft. However, the 241 heads are very close to the 243s in terms of flow. The shortblock is the same and the intake manifold exhaust (other than the catback) is all the same.

I know lighter components help w/ increased revs, but plenty of people install aftermarket heads like AFRs or TrickFlows which have standard steel valves and spin then w/o issue.

Maybe it's a powerband thing? But the car pulls strong all the way to rev limiter.

-Brian

Marc 85Z28

iTrader: (8)

241 and 243 heads are not "very close in terms of flow"

Due mainly to the cam, the LS1 doesn't make power over 6000rpm.

LS1 and LS6 shortblocks are NOT the same. Block, pistons, and rods are different.

teke184

iTrader: (5)

i think you answered your own question. those things you list are the main reason for reving higher

also

not all 01+ fbodies got the ls6 block

Cobra4B

iTrader: (9)

In 2001 all C5 Corvettes got the LS6 block and intake manifold as well as the upgraded exhaust manifolds and h-pipe. I understand that for the F-body it was hit/miss as to which setup you got, but in the C5s they all got it. 2001+ LS1/LS6s also got stronger sleeved rod bolts and the 2002+ cars got coated piston skirts to reduce slap on cold starts.

In addition to those upgrades the 2001+ cars got the 241s and a revised cam vs. the previous '97-'00 cars.

Anyone have a stock flow comparison between a 241 and 243?

redbird555

iTrader: (14)

Someone correct me if I'm wrong but didnt 2003 ls1's come with 241 heads and 04 they started with the 243?

Cobra4B

iTrader: (9)

Nah... 243s are Z06 heads and the standard LS1 never got them.

redbird555

iTrader: (14)

I definitely know that the 04-up ls1's had them atleast in the GTO so I'd imagine the corvette's would too.

PowerShift408

iTrader: (44)

I don't think GTOs got 243s until 05, when they got the LS2.

headed-ws6

iTrader: (34)

No ls1 motor in a 04 gto or vette got 243's the 05 gto and vettes got the 243's and the 799's(similar head).

MikeG

iTrader: (33)

It's all about the powerband of the LS1 vs LS6. LS1's fall off after 6k, no reason to rev higher.

Cobra4B

iTrader: (9)

You both are correct... the LS2 got the 243 heads and a 2001 Z06 cam.
Makes sense I guess... even w/ the 2001+ upgrades (intake manifold, revised cam, exhaust manifolds, etc.)? The car seems have a very linear pull to the 6200 rpm limiter... I can't imagine another 400 rpms being an issue.

MikeG

iTrader: (33)

Have you never seen a dyno graph of a stock LS1?

Cobra4B

iTrader: (9)

Never owned one until now... so no, never really paid attention to stock graphs, just know they make 305-315 rwhp stock in a C5 and 340-350 rwhp w/ headers and a tune.

Frost

iTrader: (45)

The cam is the limiter (followed by valve springs being a physical limit; over spin it at your own peril). A stock cammed LS1 is NOT pulling at 61-6200; you need to recalibrate your butt-dyno Brian

Cobra4B

iTrader: (9)

Ok... so I'll throw in some yellows and rev! Honestly the car has a very broad powerband. Definately has more low end response than my cammed LS6 and feels fairly linear all the way up... obviously it lacks the strong pull the LS6 has from 3500 on up, but it doesn't fall away.

You want to drive a car that's a slug up top? Go drive a '96-'98 2V GT mustang... car makes peak torque at like 3500 rpms and is an complete dog over 4500 and it has a 6k redline. Back in highschool me and my buddy got our best 1/4 mile times in it shifting at 5k rpms... it was his car and we'd lie to his parent telling them we were gonig to "watch" drag racing :p

Zero4488

iTrader: (10)

Here is a dyno sheet of a stock motor LS1 (241 heads). Does have some basic bolt ons. Was dyno'd on ECS's Dyno Pac. You can clearly see it drops off but not tremendously....

Ryne @ CMS

iTrader: (10)

even if your throw yellow springs on the motor, its not going make power any higher... why rev the crap out of it for no reason??

Cobra4B

iTrader: (9)

I was joking around... I'll probably just get headers and a tune and then some 3.90 gears down the road.

WKMCD

iTrader: (2)

So now you're thinking gears to this "I'm going to leave it stock" car?

Cobra4B

iTrader: (9)

Yeah man.... I "think" I'm gonna do lots of stuff, but we'll see. Car is definately getting wheels next, then after that probably some headers after i finish the kitchen floor.