I just found a 5.3 in the local bone yard. It has the 862 heads on it and was just wondering if these are the ones that flow the same as the 243 heads. Please someone let me know ASAP. Thanks guys.

 

In short NO.

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 Number 243
Head: 2001 LS6 5.7 Liter 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

Stock Head Flow Numbers
Chamber 64.45 cc-------0.100---0.200--0.300--0.400---0.500---0.550---0.600
Intake 210 cc------------62------126----184----224-----251----256----257
Exhaust 75 cc------------57------108----143----163-----176----180----183

 

^ There you go, basic 4.8/5.3 heads

799 (243) heads only came on aluminum 5.3's and GEN IV 4.8/5.3's. 243's are exclusive to LS2/6's

If the engine is a decent price, you should still grab the drivetrain regardless of head type

 

They're found on over a half dozen other engines as well.

 

I have seen 243s on LS4 engines, and several 2007-up pickups and SUVs with 5.3s

 

317's flow the same as a 243/799 head....

 

But with a larger chamber/less compression.