Big difference in cam specs for dynamic compression?

I have the timing set to around 8-10* at idle and 32* mechanical; I recently bumped it down 2* from what it was before and it helped reduce the pinging noticeably. When I first got the motor done it ran fine on mid-grade gas with a little pinging but after having 10,000 or so miles put on it it's definitely more prone to ping; I'm assuming this is from carbon buildup in the chambers and piston faces. The 256/262 Voodoo cam in it now is definitely too small for 360 cubes and 10.5:1 compression.

I'm actually looking at a particular Howards cam, it's a single-pattern grind with 275* duration and .470" lift on a 108* LSA... With my 1.6:1 rockers the actual lift would be around .500" and the longer duration bumps my dynamic CR down to 7.3:1. I think this will complement my engine better as it currently has brutal bottom-end torque but it runs out of breath by 5000 RPM. I could stand to have the torque curve moved up the RPM band a bit and not be so incredibly 'flat'.