8.5:1 = NO! Also, if you are building a motor, you might want to look at more than the M112. See the other thread. If you dont want a lot of hp.....just 500 or so, sure the M112 will be fine, but if you want anything more than that, go with something else....Whipple, KB, TVS.....
I have a 9.1:1 motor, Stage 3 heads, Stage 3 cams, and a 2.9L Whipple.....and it SUCKS driving around town at 30 mph. If it is 40, I'm fine, but below 2000 rpms, it is horrible. I wish I would have done a 10:1 CR and 14-15 psi and still been at the same level I am now.
On what you need to build the engine, I kind of like MODMAX for rotating assemblies. I have an MMR engine, and while some people say bad things, I haven't had any problems.....but then again, my builder went over it with a fine tooth comb.
8.5:1 = NO! I have a 9.1:1 motor, Stage 3 heads, Stage 3 cams, and a 2.9L Whipple.....and it SUCKS driving around town at 30 mph. If it is 40, I'm fine, but below 2000 rpms, it is horrible. I wish I would have done a 10:1 CR and 14-15 psi and still been at the same level I am now
Sorry bro but I have to disagree with you on this one. I don't think your compression ratio has anything to do with your car being a slug in lower RPM's. Last I checked the compresson ratio on an 03 cobra was only 8.5. I think your problem is your stage 3 cams. They are costing you some serious low end tq. That massive blower isn't helping either because of the ammount of power required to turn those big heavy rotors. Honeslty even with that bad ass blower I would have not gone beyond a stage 2 cam. I say this because once you step into aftermarket cams the different stages dont really add much power they simply steal it from the lower end and add it to the top. There was a GT500 cam swap done by VMP in MM&FF that demonstrated this. They didnt actually say it but if you looked at the dyno graph it was plain as day.
The old way of thinking was low compression, high boost........now it is higher compression and moderate boost. Ford must agree with that to some end because they upped the CR for the 2013 GT500 from 8.4:1 to 9.0:1 and the same is true for the v6 ecoboost. It is a 10.0:1 CR and something like 12 psi.