tnmotown

iTrader: (107)

Got the following cam going in my car and was wondering if it will clear stock 243 heads? I know they are 62cc which is a little less then my stock heads so i just wanna make sure. Also what head gaskets do you recommend with the ls6 heads and this cam?

1SLwLS1

iTrader: (6)

the clearance b/w 241/243/799 heads should be identical. The 243/799 bump compression with a smaller CC with dual quench pads, the clearances are identical

tnmotown

iTrader: (107)

^^^ good to know, i didnt know that

JPH

iTrader: (2)

It will fit.

hammertime

iTrader: (1)

Have your heads been milled to 62cc, or have you simply mis-quoted the stock size for LS6 heads (usually 64cc). The difference is only about .012" mill, but before you assume anything, you should degree the cam and measure the actual clearance.

tnmotown

iTrader: (107)

I thought stock 243 heads have 62cc? I could be wrong, and thought ls1 heads were 64cc?

hammertime

iTrader: (1)

From the Got cam/heads/rocker/machining questions about LS1, LS2, LS6? READ ME FIRST! sticky at the top of this forum....

Head cc volume = what compression ratio?

72.27cc = 9.1 CR
71.71cc = 9.2 CR
71.05cc = 9.3 CR
70.59cc = 9.4 CR
70.03cc = 9.5 CR
69.74cc = 9.6 CR
68.91cc = 9.7 CR
68.35cc = 9.8 CR
67.79cc = 9.9 CR
67.23cc = 10.0 CR
66.67cc = 10.1 CR (stock LS1 head spec)
66.11cc = 10.2 CR
65.55cc = 10.3 CR
64.99cc = 10.4 CR
64.43cc = 10.5 CR (stock LS6 head spec)
63.87cc = 10.6 CR
63.31cc = 10.7 CR
62.75cc = 10.8 CR
62.19cc = 10.9 CR
61.63cc = 11.0 CR
61.07cc = 11.1 CR
60.51cc = 11.2 CR
59.95cc = 11.3 CR
59.39cc = 11.4 CR
58.83cc = 11.5 CR
58.27cc = 11.6 CR

Also, from the New LS1 Owners - Newbie Tech forum, under the JRP's FAQ For Commonly Asked Questions sticky

Head Casting Info

Casting Number 241
Head: 1997+ LS1 5.7 Litre Passenger Car
Material: Aluminimum
Part Number:
12559806 (1997-98) Chambers = 69cc
12559853 (1999-00)
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

It takes about .005" milling of the block deck to remove 1cc of volume. It takes .007" milling to remove 1cc from an LS1 head

Cobra R

iTrader: (6)

Cant degree the G5x3, they wont give you the specs to degree it with.


Have the g5x3 in my car, pulls pretty hard starting around 3400 or so. Good that you have 4.10's already, that made a big difference in my car with the cam over 3.42's.

tnmotown

iTrader: (107)

Thanks hammertime, thats EXACTLY what i wanted to see

Cobra R, you have any times/dyno number with the g5x3 cam? And do you have cam only or other mods? a4/m6?

hammertime

iTrader: (1)

G5X3 specs have been around this forum for years, 234/242, XE-R lobes if I recall correctly. Ground at 114+4 or 112+4.

You might not get the cam card, but they can be degreed once you figure out the VE's.

tnmotown

iTrader: (107)

yep, those specs sound about right. I have the 114 lsa

Cobra R

iTrader: (6)

Trickflow 220 heads, milled to 59cc, Fast intake ported and opened up to 96mm, NW96mm throttle body, 85mm MAF, 1 7/8 ARH headers, ory, B&B catback

459/410 on the dyno, track ran a 11.8@123 stock rear with 4.10's. The clutch was probably slipping some on both the dyno and track, only had 1500 miles on it and was down to the rivets.

Cant say I agree with degree a cam off whats posted on the internet, I have seen 3-4 different specs for the cam posted on here.

bonestock99

iTrader: (1)

I have the cam on a 112+4 with stock 853 heads

tnmotown

iTrader: (107)

since i have the 114 lsa, does it have an advance built in it usually?

Also, since i'll most likely be getting some ls6 heads (which shows 64cc), Im thinking about milling them down to 62cc. Would that be too much with the cam? Just want to bump up the compression some

bigdawg6114

can you have 55cc 241 heads on a 6.0 on pump gas?