10.3 CR and .040" quench sounds good. The "rule of thumb" with good quench, street driven and a moderate performance cam is 10.4/10.5 max. Just a touch conservative sounds good. I went with 10.2/.040" quench and it has been very robust against detonation with a 243@.050 intake duration cam. That way if I run it hard and long, or get a tank of less than perfect tank of gas, I shouldn't hurt the engine.