Need some opinion's here,pro's and con's of both if ya would

Thanks in advance

 

well what all is gonna be done to the engine, or are you just goin with heads.

 

Do you plan on having boost in the future? If so, the added compression of the 5.3's won't be helping you out. I have ported LS6 heads because heads are expensive, and I'd like the option to add some boost later if I want.

If you plan on keeping it N/A or you're adding nitrous down the road, it's hard to beat the value of the 5.3's.

 

Right now Im just trying to decide what i'll need to look for.Its gonna be a na build....MAYBE nitrous later on down the road. Its not a dd,but it is my weekend street/strip car

Also so far I havent even picked out a cam,but from what I read the 5.3 heads will give me more tq,and much higher compresion?

 

The only advantage to the 5.3 heads is a smaller combustion chamber, yielding higher compression. The LS6 heads start with alot better port, and I question whether a quality ported 5.3 can compete with a quality ported LS6 since the floor of the runners are different.

The advantage to the LS6 head is you can get great flow numbers with the stock size valves and have better p/v clearance.

 

5.3

.300 208
.400 257
.500 290
.600 312



LS6

.100" 72
.200" 142
.300" 205
.400" 255
.500" 286
.600" 305
.650" 310


Right off of texas speeds site.

I went with the 5.3s, since they flow awesome plus the added compression.

 

Thanks, that kinda sells me on the 5.3's....so whats the good casting number to look for?

 

706 is the casting number.

 

i went with 5.3's also from tsp,i'm glad i went those cause i want to spray later,just waiting on shipping.

 

what about the 862 5.3 castings? do they flow the same as the 706;s?

 

i belive the 863 casting number is the steel. im not 100% sure though.

 

i have aluminum 862's

 

huh i dont know then if you can get me gm part numbers i can check to see if there different valves, or what not i might be that 862 are for a flex fuel motor and the 706 are for the gas motor.

 

My 5.3L Sierra has 243s on it, bone stock. Just FYI.

I'm looking at the same heads myself for the Camaro, and I think right now I'm leaning towards the 5.3s because of the higher compression and flow numbers.

 

My buddy's new 4.8 does to...are they the same as the LS6/2 heads?

 

they are 1.89 and 1.55 same everthing im not sure on the chamber size but im sure it is

 

799's are the Flex Fuel/Active Fuel Management heads, My PRC 5.3's are 862 casting which are the older 5.3L casting. GM stopped making the 862's and just went with 243's.

 

Here is a list of a few casting #'s:

933 97 aluminum perimeter bolt 5.7
806 97-98 aluminum perimeter bolt 5.7
853 99-00 aluminum center bolt 5.7
241 01-03 aluminum center bolt 5.7 (some late MY00 cars got 241 castings)
243 LS6 aluminum center bolt 5.7
862 and 706 99 and up 4.8-5.3 truck heads
873 99-00 LQ4 6.0 iron center bolt heads
317 01 and up LQ4 6.0 aluminum center bolt heads
035 02 and up LQ9 6.0 aluminum center bolt heads

Even more 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