Dynamic Compression Ratio

Save yourself some hassle, and possible screwups and have someone spec out a cam for you. Your static compression sounds a bit low anyway. My last 340 had a comp. of 9.5 and easily could have handled another full point without detonation or "rattle''. My stroker is 11.5 and with an open chamber head, I'm still only using 1 gal. of 114 race fuel per tank. Closed chamber heads typically allow more comp. than open, also. Smaller dia. pistons like your 340/373 also allow for higher comp. simply because of better flame propagation, especially with flat top pistons