the problem with running too small of a cam in an engine with alot of compression is detonation. After searching for this piston I came up with a 47.1 cc dome or a 43.1 cc dome. Not sure which one you have but they are both under the same general part number. With the 43 cc, zero deck, and .040 gasket, I came up with 11.89 CR , and with the 47cc dome I came up with 12.49CR!! I think with 11.8 CR you are right on the verge of needing to run race gas, 98 is awesome but 110 sounds better. I would be weary of running a cam with only 224 degrees @ .050 lift. Sounds very small for a 12 to 1 engine. If you are dead set on using this motor I would use 110 octane, and retard the timing alot. If you hear detonation I would get off the gas real quick, cause it don't take long for a piston to melt under these conditions. What will the motor be used for? I would at least shoot for 240 degrees @ .050 on the cam duration. Plus those old magnum cams are outdated, much more potential with an Extreme Energy cam!!