lt1le2

iTrader: (1)

Alright guys have a question.

Trying to debate if I should go ls3 top end or ported 243’s.. getting mixed reviews of people saying 243’s I would get better velocity and better power others are saying ls3 is way to go I have a BTR Stage 4 LS3 Stage IV 3 Bolt Cam 233/250 .619"/.595" 113+5 in the shortblock now. this is a street only car and the block will be going in a 99 Trans-Am. I need some opinions on what top end to go with. I don’t want to pay 1200 for CNC 243’s when the LS3 heads would equal that stock almost.. helpppp engine specs are below and this is NA setup only.



L76 Build 6.0 370 Motor Build Block Casting 12568952
Machined Bore Size 4.030 with STD/STD Crank 24X wet Magged Chamfered and polished
Flattop Coated C10218-030 Mahle Pistons Factory Floater Rods Reman.
Wide Cam Bearings with King racing Mains DOD Ports Plugged

NAVYBLUE210

That cam and OE LS3 heads will make more power from 5500-7000+ RPM
With compression 11.0-11.5:1 gas, or 12.5:1+ E85 and a short runner intake,
FAST Mid, or Holley Sniper. It Depends on application & where
you want your power band. Well ported 243s and a different cam something like
~232/238 would be more responsive & fun on the street from 2000-6000 RPM
and pretty close to OE LS3s at peak.
If you don't want to spin that high and still use the LS3 Heads I would definitely
change to a stage 2 or smaller custom cam and use a ported stock intake.
Gears, the whole combo & an excellent tune will make or break.
My .02
Good Luck

KCS

iTrader: (20)

I’d be surprised if that cam didn’t have PTV problems with those flat top pistons.

What transmission will this he paired with?

lt1le2

iTrader: (1)

Sounds like from what you are saying is stick to 243 heads since it’s street car on lower end HP snTQ?

lt1le2

iTrader: (1)

It’s a fully built Auto triple clutch billet 4000 stall and 410 gears.

NAVYBLUE210

With your stall and gears, if it were me I would run the Cam Motion Titan 3 LS3 227/237 113*+3.5* .624"/.604"
Better PTV (still need to check) still pull to 6500+, especially with the shorter runner, Will drive Much better
as a street car. Much easier to tune also.

bortous

I was in the same boat as you with the head choice for my LS2 6.0
I was considering ported 243 instead of the LS3 heads but I ended up choosing a set of CNC ported LS3.
One thing I did notice though on my 6.0 litre is that the torque did not feel as intense in the low end and torque under the curve just didn't feel as good.
Only from 4000rpm+ the torque was good and once you hit 5000rpm+ the LS3 head shined..
If I had a 6.0 litre and I wanted to use a OE head I would definitely stick with the 243 head for this engine size.
They flow almost as good as a stock LS3 head once CNC ported but will provide better torque in the low and mid range.
When I did a 408 stroker the ls3 heads really woke up. Not quite to the 243 level in the low end but close in terms of feel and under the curve power.
Once you hit 3000rpm though with these heads in the stroker, they really shine in terms of intensity.

Hope my experience helps you out

bortous

By the way when my engine was a 6.0 litre I had used that lingenfelter 229/242 114 LSA camshaft.
I made nearly 480rwhp with a FAST 102mm 11:5.1 compression and a 3000rpm stall converter which was insane.
The LS3 heads do make power but on a 6.0 litre you do sacrifice those things mentioned in the post above.

lt1le2

iTrader: (1)

Thank you everyone for the reply’s... think I am going to stick with 243’s since it’s a street car and want the bottom end. My only debate now is the cam lol I thought I was set.. I loved the lope sound from the BTR stage 4 I will defiantly check P2V. BTR guys told me should be fine as long as heads are not milled. This is what they told me.

NAVYBLUE210

That current cam will be Hugely disappointing with 243s Ported or not. I would suggest
Cam Motion Titan 5 LS1 232/238 113+4 .624"/.604" still a good sized cam that will
perform and drive worlds better. Or Cam Motion Custom, Great customer service, get
exactly what you want for your combo and goals. Easy enough to sell your stage4 &
LS 3 Heads to a dedicated race build.

lt1le2

iTrader: (1)

Cam motion is recommending I get custom 232/242 113+3 620 intake 612 exhaust 11 degrees

NAVYBLUE210

That will be a Great Cam with a Ported MMS MSD Intake to 7000+ or a Holley Snyper,
A Ported Fast 102 would work better with the Titan 5 ~6500.
Just my .02 Splitting hairs now, you are definetely in the sweet spot for
370",HCI,stall and gears.

DualQuadDave

iTrader: (6)

Call AI or Greg Good(Motion Raceworks) for a good CNC on the 243's and go for the bigger intake valve. They run great. Make sure you figure what chamber you need and have them shave to suit. Good luck, it'll run good!