Is there any differences between the ls1 and ls6 head? I don't remember hearing any changes in the head when GM introduced the ls6. Are the castings the same?

 

Yes, they are different. No the castings are not the same. An LS6 will flow a fair amount more air than an LS1 head. A ported LS6 head will flow a tad more than a ported LS1 head. Depends on the porting work obviously. LS6 heads usually flow a lot better at higher lifts like .580+.

 

Like he said, LS6 heads really start to shine at higher lifts.

 

LS6 heads can theoretically flow like 320-330 cfm at higher lifts and you will typically see LS1 heads doing 290-310 cfm. Those are very very general ranges, since a bigger set of valves can add 10 cfm to a set of heads.

 

Yah, the LS6 heads are definitely better. When I ordered my MTI stage 2 heads, Jayson told me that the stage 2 LS6s would probably worth 10 hp over LS1 stage 2 heads on my heads/cam combo. He also told me that on a large displacement motor The LS6 heads have a larger advantage over the LS1 castings. When I ordered my heads a year and a half ago, I could not justify spending 1200 more dollars for 10 extra rwhp. But now, I wish I would have done it.

Jordan

 

the LS6 heads have a D shaped exhaust port.

 

what do the ls6 heads come on?

 

LS6 heads have a smaller combustion chamber as well right?

 

Z06 Corvettes.

 

Below is some specs on both the 5.7 LS1 and LS6 heads. This info was posted by someone else here a while ago.

Casting Number 241
LS1 / 5.7L Passenger Car and Corvette
P/N 12559853 (97-00)
P/N 12564241 (01+)
Material: Aluminimum
Combustion Chamber Volume: 66.67cc
Compression Ratio: 10.1:1
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches
___________________________________________

Casting Number 243
LS6 / 5.7L "ZO6" Corvette
P/N 12564243
Material: Aluminimum
Combustion Chamber Volume: 64.45cc
Compression Ratio: 10.5:1
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

As others have said, the exhaust port design is different between the heads. The LS6 has a "D" shaped exhaust port, while the LS1 does not. Bone stock, the LS6 will certainly flow better. Once fully ported and using the same size valves, I believe they both will flow about the same. Maybe just slightly better on the LS6 heads.

Ron,

 

Tin Indian,
I am pretty sure that the intake and exhaust volums changed from 2000-2001/2 I am pretty sure in 01/02 they also went to 210cc I and 75cc E. the GM H/P mag I have states that any how but it would not be the first mistake a magazine has made? Just thought I'd throw my .02 in.

 

Everybody missed on of the most important differences:

The LS6 has a larger "short side" runner radius than the LS1. In effect, the air entering an LS1 combustion chamber makes a sharper turn from the intake port to the valve than with an LS6 head.

My fluid dynamics professor would call this "making the air angry" by forcing it around the tighter radius.