What does 241 casted on the heads mean?

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Jul 12, 2003 | 08:21 AM

CamaroSS

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From: Tampa, FL

What does 241 casted on the heads mean?

My cylinder heads have the number 241 on them, what does this mean? Does this support my theory that I have a "freak"? Here, check out my very very very unexpected kill. https://ls1tech.com/threads/showflat...amp;PHPSESSID=

Jul 12, 2003 | 09:20 AM

TVWilkes

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From: RainbowCity,Alabama

Re: What does 241 casted on the heads mean?

241 is a 2000 up 5.7 head casting number.

Jul 12, 2003 | 10:22 AM

NightHawk

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From: Sarasota, FL

Re: What does 241 casted on the heads mean?

241 means it's an LS1 head. There's a different number for the LS6 head, but it seems to escape my memory at the moment...

Jul 12, 2003 | 10:23 AM

CHRISPY

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Re: What does 241 casted on the heads mean?

I also think people have been seeing higher stock flow numbers out of the 241 casting. (Better base for porting)

I believe JPR has spoken about it before.

cheers,
Chris

Jul 12, 2003 | 10:34 AM

TVWilkes

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From: RainbowCity,Alabama

Re: What does 241 casted on the heads mean?

LS6 casting is 243

Jul 13, 2003 | 03:16 AM

Cal

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From: Northern Utah

Re: What does 241 casted on the heads mean?

If you look down the intake port of a 241 head you can see a LOT of room for improvement via porting! It may really be better than the earlier LS1 head design, though.

Jul 13, 2003 | 04:12 AM

strife

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Re: What does 241 casted on the heads mean?

out of May GMHTP

Casting Number 241
Head: 1997+ LS1 5.7 Litre Passenger Car
Material: Aluminimum
Part Number:
12559853 (1997-98)
12559853 (1999-00) (not sure why same PN)
12564241 (2001-03)
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
Head: 2001 LS6 5.7 Litre Passenger Car
Material: Aluminimum
Part Number:
12564243
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

Casting Number 706
Head: 1999+ LR4 4.8 Litre Truck
1999+ LM4 /LM7 5.3 Litre Truck
Material: Aluminimum
Part Number:
12559852
12561706
Combustion Chamber Volume: 61.15cc
Compression Ratio: 9.5:1
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 1.89 inches
Exhaust Valve Diameter: 1.55 inches

Casting Number 373
Head: 1999-2000 LQ4 6.0 Litre Truck
Material: Cast Iron
Part Number:
12561873
Combustion Chamber Volume: 71.06cc
Compression Ratio: 9.5:1
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

Casting Number 317
Head: 2001+ LQ4 6.0 Litre Truck
Material: Aluminimum
Part Number:
12572035
Combustion Chamber Volume: 71.06cc
Compression Ratio: 10:1
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

Head: GMPP C5R
Material: Aluminimum
Part Number:
12480005
Combustion Chamber Volume: 38cc
Compression Ratio:
Intake Port Volume:
Exhaust Port Volume: 70cc

Head: GMPP C5R
Material: Aluminimum
Part Number:
12480025
Combustion Chamber Volume: 38cc
Compression Ratio:
Intake Port Volume:
Exhaust Port Volume: 70cc

Head: GMPP C5R
Material: Aluminimum
Part Number:
124800290
Combustion Chamber Volume: <30cc
Compression Ratio:
Intake Port Volume:
Exhaust Port Volume: 70cc