asb2106

iTrader: (2)

I recently put together a LR4 short block with 799 heads and an LS9 head gasket.

I have comp cam push rods at 7.4", an LS9 cam, pac .650 springs..

The engine runs, and will build boost, but takes FOREVER (30+ seconds) to get from 1200-2000rpm. Pulls up through the RPMS slowely until boost comes on and then it goes like crazy.

Some fleabay turbos - Compressor trim: Compressor Wheel diameter: 54.28 /71.32 Turbine Wheel diameter: 55.79 /63.36 Exhaust Trim: .63ar

I found this comparison..

Casting Number 243 (and if Im reading this right the 243 is the same as the 799)
Head: 2001 LS6 5.7 Liter Passenger Car
Material: Aluminum
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



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

***********************************

So is the 3.3cc and 7 layer steel head gaskets taking the compression really low causing me to drag *** that much, or do I have something else going on?

If it does happen to be compression, can I deck down the 799s at all to get the CR back up?

Will I need to get different push rods at that point as well?

windmill

iTrader: (4)

seems like you forgot 1 thing to tell,,,, what about the converter you have,, what stall speed?

asb2106

iTrader: (2)

Oh Im sorry. Stock converter, on a l60.

I bought the truck with a bad trans, had my trans guy freshen it up with hardened input shaft and shift bands, and whatever else he recommended.

He also put a new stock converter in there.

I drove the 5.3 with the new converter and trans for roughly 500 miles before deciding to put the lr4 tt motor in it.

Once the 60 lets go I've got a 80 ready that Ill have looked over and toss a transgo kit in there.