Im looking to bump the CR up just a little on my h/c install and was wondering what would help, could I go with a .040 Cometicgasket to bring it up some? I am installing the MTI S2E heads on the stock shortblock..Im unsure as to what the CR will be just installing these,Im assuming as they are unmilled to will remain the stock CR..Thanks

 

why not mill them .030?

 

well, I was concerned with not being able to use a larger cam without flycutting the pistons..Not really interested in cutting the pistons as Im gonna spray this pretty hard..I wonder how big of cam I can go with if I had them cut? Im looking at the MTI cams, X or G1..

 

just cut em .050 then. you'll hurt the rings LONG before you blow thru the meat of the piston (which is what your cutting into). just make sure to smooth the edges because thats where the detonation will hit and blow through first

 

Not interested in cutting into the pistons or milling the heads at this point, can I use a different gasket or is it just not happening?

 

first off what castings are your heads?

 

MTI S2E's..

 

i can see that but what CASTING, the S2E's come in 5.3, 5.7, and 6.0. all which give you a different compression ratio.

 

5.7's..Sorry for the trouble..

 

with the .040 gasket and unmilled 5.7's your looking at a .2-.3 bump in compression. hardly worth it to me. mill the heads instead, should of bought the 5.3's if you wanted more compresssion.

 

well, I wasnt look for a huge jump in compression as I do not want to run race gas, just thought I could get a little by going to a different gasket..Also with milling the heads wouldnt I lose the ability ro run a larger camshaft, Im going to be running something close to .600 lift..Im fairly new to the LS1 cars, this will be my first "street car" and Ive got certain things I just dont want to deal with and anything but pump gas is one of them..

 

good pump gas can easily be run on a setup with 11.1 compression tuned. your not even close to a point where race gas is needed. yes, milling will loose crucial pistion to valve clearance, one reason to go with the 5.3's if you want higher compression.

 

Thanks for the info, I went with the suggestion of Dave @ MTI when picking the castings for my setup and I just thought Id ask for some more opinions on the gaskets, I think Ill just stick with a Cometic stock size...Now to find a decent cam that'll work on the motor as well as the NX MAF kit I just bought...

 

jrp, what is "good pump gas"? I will be running 91 octane (not Cali stuff) in my car and would like to bump compression past stock but don't want any detonation issues! I was going to use the .040 Cometics but maybe I can get away with milling the heads .030?

Thanks

 

as long as you have a "safe" tune, you will be okay..... just don't put your foot down while under 2k rpm or it might ping a little bit

 

Thanks for the reply. No offence but I don't want any kind of tune that will ping! If I can't use a healthy dose of throttle below 2000rpm then I better stick with stock CR! Do all high-comp LS1s suffer from low rpm, WOT ping?

 

if n/a, it won't hurt much. my buddies mustang pings all the time if you put your foot down in OD with the a/c on........ been like that for over 2 years and hasn't had a single problem. just be aware and nothing will go wrong

 

I say ! These high-tech LS1 engines should NOT ping on premium fuel. IMO, if you are getting detonation I think you are running too high a CR or have a bad tune. Maybe the 'ol Mustang is a different story.

 

91 premium fuel? thats squarel **** where we come from!