2056 build compression ratio dilema Options

[jjs3rd914]

Building a 2056, want good low end torque and drivability. Car has AC. Targeting 115-125 HP

GA 2L case, stock 2L crank rods, new AA 96mm pistons, biral cylinders
New AA 2L heads with 44/36 valves
Webcam 086 cam
Weber 40IDF dual carbs

After numerous searches seem like 8.5 is optimal compression ratio (CR) and the build should get me the targeted HP.

BUT finding during assembly, with a deck height of .065" (with .010 barrel spacer) 60 cc head volume which includes 2CC for the piston valve recess, I am only getting 8.1.

So option are to leave alone and go with 8.1CR
or
Machine heads to loose about 6CC
or machine barrels to reduce deck height. Was told must use a barrel spacer and am using the thinnest I can find at .010.

To get the targetd HP do I need to get to a CR of 8.5, or will 8.1 get me there.?

Am really confused about the whole CR optimal number for what I want.

Thanks

jjs3rd914

[nditiz1]

Conedodger is correct you can go higher.

The dilemma you may run into is that you take so much off the bottom that your DH would cause a valve opening interference issue. With these pistons having the relief valley I don't really see that as a problem, but every setup is different.

I have never read that the base gasket is required. I was told just use some Curil T or 518 Loctite and you should be sealed and have no issues. If you are worried about cutting too much off and almost being flush with the cooling fin which happened on 2 of my cylinders you could have the shop mill a step like they cam from the factory. So they would be milling the cooling fin.

I would have them cut .010 off the bottom and not use the base shim - that would net you .045 DH which equates to 8.5 CR

OR

you could have them cut .020 off the bottom, (what I had cut) then use the base shim to get you to .045 DH