Hey guys, I was wondering what kind of SCR you have been able to get away with on 93 octane. I am in the process of gathering parts for a hybrid motor I am going to build. I am using 12cc dished pistons +.030" (.75mm) in a 3.1 with FWD heads (aluminum) that will decrease my combustion chamber from 48.5cc to 27cc. With the stock sized head gaskets (.040" compressed height) I will be at 11.98:1. With removing 1cc of material from the chamber and .060" gaskets, 10.99:1 can be obtained.

I know cam selection can make a difference when high compression is used and this will be a boosted motor when finished. I just want to know if I can get away with pump gas and low boost for street driving and use race gas at the track. I don't know if it makes a difference but MegaSquirt is going to be used as my EMS (with spark control).

 

The 60* V6 motors are a pretty different animal than what most of us are used to here. The FI is pretty advanced IIRC, so you can get away with more compression due to good fuel mixing. I don't know the bore/stroke ratio with those motors, but it has a pretty big effect in some motors.
This is why i'm not very comfortable giving you any kind of specific solid advice on that motor, or comparisons to iron headed SBC setups. Apples to oranges eh?

But i'll rattle off a bit to keep my fingers from getting bored

12:1 or 11:1 and you want to boost it later? Is there something i'm missing? If you want to run any boost at all, keep it below 10:1. That'd be VERY modest boost. If you want to go fast, shoot for 8:1 CR or so. Boost gives you a lot more power than CR does.

If possible, use studs and carve o-rings into the heads. It's pretty cheap insurance to a failed head gasket if you're going to run lots of boost.

Mind your quench, a .060" gasket shouldn't even enter your mind. If you're at the stage of doing your homework on a motor build (good for you! Not just throwing it together all unplanned and whatnot), then you can plan to avoid that abysmal slap in the face to quench.

.040" quench distance, no more.

 

The stock motor has more quench than that. The deck clearance is .0165 and gaskets are .040 compressed height (I'm not arguing, confused rather).

 

Stock doesn't mean it's ideal. Many stock motors aren't idealized.

You might be right though, most SBC's are at .040" quench stock, and that's supposed to be "right" ..... for an SBC. Who knows on those motors. Maybe someone else can shed some more light on the rest of your questions.