F-BodyGuy98

im thinking of purchasing some 6.0l truck heads as i have heard and read that they work great for a boosted street application...but i am also looking to put the LS series forced induction cam in from EPP as well, what would this set up drop my compression to with a stock block and internals?

Disturbed Bird

iTrader: (9)

Using 3.898 bore, 3.622 stroke, -0.008 deck hight, 0.00 dish pistons, and 0.060 gasket thickness this is what i come up with...

9.1:1 = 77.27
9.2:1 = 76.21
9.3:1 = 75.16
9.4:1 = 74.15
9.5:1 = 73.16
9.6:1 = 72.19
9.7:1 = 71.24 (Approximate Combustion chamber of 6.0L heads +/-)
9.8:1 = 70.32
9.9:1 = 69.41
10.0:1 = 68.53
10.1:1 = 67.66
10.2:1 = 66.67 (Stock LS1 Head)
10.3:1 = 65.96
10.4:1 = 65.18
10.5:1 = 64.45 (Stock LS6 Head)
10.6:1 = 63.61
10.7:1 = 62.85
10.8:1 = 62.10
10.9:1 = 61.37 (Approximate Combustion chamber of 5.3L heads +/-)
11.0:1 = 60.66
11.1:1 = 59.96
11.2:1 = 59.27
11.3:1 = 58.60
11.4:1 = 57.93
11.5:1 = 57.28
11.6:1 = 56.65
11.7:1 = 56.02
11.8:1 = 55.41
11.9:1 = 54.81
12.0:1 = 54.20
15.4:1 = 38.00 (Stock C5R Head)

Although the stock ls1 compression figure may seem off, i have seen a lot of sites selling "stock ls1 long block" with a 10.2:1 compression ratio (i.e. pace performance). Perhaps 10.2:1 is the true compression ratio of a stock LS1 motor and GM says otherwise. GM has a nice way of making up their own horsepower and torque ratings for motors as they see fit, perhaps they figure 10:1 is just easier to say. The LS6 compression ratio seems right on according to the combustion chamber and the calculations. Since no one has ever been able to give a diffinitive answer on the actual size of a 6.0L combustion chambers (i've seen anywhere from 70cc-72cc) i think it is safe to assume that 6.0L heads would not lower a stock LS1/LS6 motor's compression ratio any more than 9.6:1.

F-BodyGuy98

how would 9.6:1 do with about 10psi being pushed through it? would it hold up?

elias_799

iTrader: (8)

^^^ you should be somewhere near the 500whp mark on 10 psi. and that is one the edge of the factory pistons. it will work for a while, but do not be surprised when it blows up.

F-BodyGuy98

yeah, i know its gonna go after a while, ive heard that these bottom ends are good for "about" 600 at the motor stock...in a sense im kinda wanting to push her to her limit and see how much she can and will take...i mean, when i first put in my boost controller and had the vaccumn lines backwards to were i pretty much eliminated the waste gate, i was driving around on like 15 psi for a week and she took it like a champ...im just wondering if a fi cam and these heads would be enough to get it to last a bit longer until i can build a motor. cause im getting my hands on a complete 6.0l and was gonna put the heads on the stock block until i can get the funds to do some real work with the 6.0l block...