bigfatls6

iTrader: (34)

I have a forged 347 and the heads I have are a stage 2 GTP 5.3 head with the 202 and 1.57 valves and have 58cc chambers. I am looking for a thicker head gasket to bring my compression down a little bit. I would rather not have to buy the cometic head gaskets if possible.
I also need some help figureing out what my compression ratio is. I want to get it to where I can run 93 octane with out worry of detonation.
Here are some of the specs. on my engine.

probe piston part# 14217-003
3.0cc valve relief volume
Bore 3.902
Stroke 3.622
rod 6.125
I Am pretty sure the piston sits 10 thousanths out side of the cylinder.
My heads are a 862 casting 5.3 head with 202 intake and 1.57 exhaust valves.
The cam I am going to use is a futural motor sports f13-112
With an intake duration of 230 and intake valve lift .595
The exhaust duration is 232.5 and exhaust valve lift .587
I have the cam card if more info is needed.

Thanks in advance for any help offered.

HSV-GTS-300

405HP_Z06

iTrader: (11)

Here it is using a stock GM 5.7L MLS head gasket. The SCR below is perfectly acceptable and will run great on the street. What SCR were you shooting for?

DCR calculation based on 68.5 IVC event. Standard disclaimer concerning DCR.

bigfatls6

iTrader: (34)

How would I find the IVC @ .006? Would that be info on my cam card or what? If you will let me know I will try to get it for you. Thanks for the info above it is very much apreciated. I just got a valve job and stuff done on the heads before they did the valve job the heads were 58ccs they said they just barely touched the surface where the combustion chambers are to clean them up. I am not really sure if that would have changed the 58cc much but it shouldn't have. I just want the car to run on 93 octane with out risk of detonation and be able to run with optimum timing if possible. If some one can please post the part# and brand of a good head gasket I would also apreciate it.

405HP_Z06

iTrader: (11)

Head gasket part numbers and specs are in post #2. The part number for the stock GM 5.7L MLS is 12589226.

A valve job could change the CC volume, you would need to measure to verify size.

To approximate IVC@.006, you need intake and exhaust duration @ .006, intake center line, and lobe separation angle.

LS1C5Vette

iTrader: (11)

Sry to jump in but where can I download this program you are using?

bigfatls6

iTrader: (34)

Here is the info off of my cam card
Engine: LS1
Grind # 230-232-12
Core: 334102
Lobe Size bc/ht IN: EX:
Enter (2): 2
Camshaft Data= 4 crnk deg
Duration at 0.05 IN
Intake- rocker ratio=1.7
Lash 23 24 25 Hyd IN
Exhaust- rocker ratio=1.7
Lash 23 24 25 Hyd IN


Install Cam on * * below Cyl# 1
Intake & Exhaust
Lobe Seperation= 112.1 Cam Deg
Valve overlap=7 Crank Deg
Intake
Valve Open= 6.5 ‘BTDC
*Centerline---> 108.1 ‘ATDC
Valve close= 43.5 ‘ABDC
Duration---> 230 Crank Deg
Lobe shift= .35039 IN
Valve Lift---> .59567 IN
Lobe area= 28.09 IN * Deg
Exhaust
Valve open= 52.1 ‘BBDC
*Centerline---> 116.1 ‘BTDC
Valve close= .4 ‘ATDC
Duration---> 232.5 Crank Deg
Lobe shift= .34531 IN
Valve Lift---> .58704 IN
Lobe area= 28.02 IN * Deg

405HP_Z06

iTrader: (11)

www.performancetrends.com

Compression Ratio Calculator

bigfatls6

iTrader: (34)

Is there a way to measure the cc on the combustion chamber other than taking the heads back to the machine shop? I Know you can use water and just add it to the combustion chamber but how do you get the head set up to measure it correctly?

405HP_Z06

iTrader: (11)

DCR added and image updated.

From where I'm sitting, using the GM 5.7L gasket for this would put you right in the optimum zone.

To measure the combustion chambers you need a burrett and plate to seal the chamber. Add water from the burrett until the chamber is full and verify volume from the burrett.