862 vs. 241...

[jrbonds]

Need to shut a teenager up about the difference in the way they flow. Googled it to no avail.

Anyone know where I could find this information?

He put 862 heads on his LS1 to "bump" up his compression.

[ls1camino]

Casting Number 706 and 862
Head: 1999+ 4.8L / 5.3 Liter Truck
Material: Aluminimum
Part Number:
12559862
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

Stock Head Flow Numbers
Chamber 61.15 cc----0.100--0.200--0.300-- 0.400--0.500---0.550---0.600
Intake 200 cc----------63 ---128----179-----210----218----221-----226
Exhaust 70 cc----------54 -- 93 ----121----145-----163----168----174

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Casting Numbers 241, 806, 853
Head: 1997+ LS1 5.7 Liter Passenger Car
Material: Aluminimum
Part Number:
12559806 (1997-98) Chambers = 69cc
12559853 (1999-00)
12564241 (2000-03)
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

Stock Head Flow Numbers
Chamber 66.67 cc------0.100--0.200---0.300---0.400---0.500---0.550--0.600
Intake 200 cc------------67----122-----178-----215-----219-----223---227
Exhaust 70 cc------------52-----97-----133-----156-----170-----76----180

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

He's actually right...due to the smaller combustion chamber, he actually bumped his compression slightly.

While this is the case, all of the work he put into doing that with stock 862 heads is barely worth the gain. He would have been better off slightly milling and porting the intake and exhaust ports as well as having LS1 sized valves installed. As you can see the 5.3 heads have smaller valves and are probably hurting his gains If he just swapped heads and nothing else he didn't gain much.

[jrbonds]

Thank you so much!!!!!

[ls1camino]

[SSwt00SS]

agreed...imo, running a 5.3 head vs. a ported/milled 5.7 head is a step backwards for the reasons ls1camino detailed above.

sure, he may have 'bumped/increased' the c/r but running the smaller head he definitely is not getting the most potential for time, money invested, etc. with that set-up.

[jesselee83189]

I have an 04 gto with 241 heads. I found a set of 5.3 heads off a Chevy truck for $100... Is it worth it to get them cnc'd vs having the ls1 heads cnc'd?

[2002ssslp]

I have an 04 gto with 241 heads. I found a set of 5.3 heads off a Chevy truck for $100... Is it worth it to get them cnc'd vs having the ls1 heads cnc'd?

I thought the 2004 GTO had 243 heads

[jesselee83189]

Nope... 241... 05-06 ls2 gto had the 243s