I'm at work now and don't remember which calculator I used, but last night I used compression calculator that had the LS1 spec already in it: the results came back at 9:1. It seemed a little low so I just wanted to see if someone could check my results. This will be for a boosted application so it's not all bad if that's correct...it's surprising low to me.

3.905 bore
3.622 stroke (stock)
-4cc forged Probe pistons
72cc 317 6.0 liter heads
.055 MLS head gasket

Let me know if you come up with the same thing. Thanks!

 

On the c5frc.com calculator I came up with 9:1

Using another calculator I came up with 9.054:1 SCR

 

~9.29:1 static. would need cam specs for dynamic.

 

I get 9.30:1 SCR.

 

Cam is a TSP 233/239 .598/.605 113lsa. I have no idea where the cam card is to get the other info...

 

would need intake duration @ .006 or intake valve closing degrees for the dynamic although i wouldn't get too hung up on the dynamic ratio.

 

http://www.csgnetwork.com/compcalc.html

I like that one.......

 

What is your deck height (.xxx inches in or out of the hole?) Assuming it is excatly 0, using the actual formula for compression ratio, it would be 9.1912:1, or rounded off, 9.2:1