mr slow

Okay I have done a little searching and haven't quite found the educated answers or true world experiences that I am looking for.

Okay so I have a high compression N/A 408(around 11.3-1) and I am looking at trying to lower the comp enough to put some boost on it without pulling the motor back out. I am not looking at putting a lot of boost on it....maybe 10-12 pounds at max.

I have some cnc'd ls3 heads that have standard 68cc chambers, I have read over at yellow bullet forums that the chambers can be opened up to around 75cc. Is this possible and what are the pros and cons of ding this.

I also have .051 4.060 cometic gaskets and I see that they offer the same gasket but in a .075 thickness. I know that running a thicker head gasket is not ideal that's why I wanted to see if anyone has any real world experience with these or educated info.

Also the pistons are Wiseco -3cc flat tops.

00duvall

iTrader: (7)

What type of fuel? E85 ur good 93 plus meth good?The most important part is the tuner.I wouldnt change compression. Tfry and get a specd camfor ur set up. Cam will helpwith high compression and boost.

mr slow

I would love to be able to run it on just 93 and then if needed meth but I know that's pushing it. If I had to run 93 and meth all the time I wouldn't mind too much. I would for sure get a new cam spec'd.

mr slow

I have plenty of access to race gas as well but I would hate to be restricted to an area where it is available.

HexenLord

93 with meth and 8 lbs should be fine. E85 would let you push it to 12 lbs.

Honestly you could get more than that out of it, but those are pretty safe numbers.

SwampWS6

iTrader: (7)

Im in kinda the same situation you are but with a LT1 383. My CR is 10:5 with 80# injectors. I will be running E85 with a max of 12#s of boost. I want to run more but I would then have to do meth injection. The only thing that is hurting me is the LT1 PCM. I could run more boost and HP if I had a LS PCM

But if guys are suggesting you can run over 12#s with E85 with 11 + CR then I guess everything should be ok..........

ttls1coupe

I have a 402 11.5 compression on e85 and I run 24lbs and make 1056hp. Flat top pistons and L92 heads 72cc. I have a holley hp Computer system on it. But it's all in your turner for sure.

SwampWS6

iTrader: (7)

Wow! Their is hope for me after all. No meth injection????

mr slow

^^wow no kidding! That is awesome, really good news to hear. Would you mind shedding a little more light on your set up? Like head gasket thickness? On the 72cc chambers...how much meat was left, could they be opened up more?

mr slow

bump...

mr slow

I mean if you think about it a stock ls1 has around what 10.4 to 1 and people run 10-12 pounds on them all day long with no meth or race gas or anything fancy. If a stock motor can handle 10 pounds then I would think a fully forged motor would too.

SwampWS6

iTrader: (7)

Ive read many places where stock LS1 CR is 10:1 not 10:4. A LT1 stock CR is 10:4. A LS6 is around 10:5. I agree with you on the a forged motor should hold 10-12#, but I wouldnt go too extreme unless its an all out race motor......

mr slow

Well at 10-12 pounds we shouldn't really be worrying too much about the strength of the internals as stock ls1 internals can handle that but what should be worried about more is detonation and destroying pistons buuut like said a stock ls1, with whatever its exact comp ratio is, can do that...I am pretty sure it can be done without running any meth or anything fancy before getting into any detonation. I am pretty sure I am going to try it.

mr slow

Thanks for the feed back everyone