don't know about the EQ heads, but stock magnums don't have a lot of meat on the port roof to cut down the spring seats...when I did my magnum 318, I had the valves sunk about .030 on the valve job, and used Hughes #1110 springs and 2.2L retainers/magnum locks. gave me ~1.64"IH and about .54-.5500" of potential lift before getting into spring binding and valve guide clearance concerns.

I'd see if bullet cams can regrind your existing stock cam, or grind you a new one. I'd use the HR278/340B lobe for the intake and exhaust. magnums have really good intake/exhaust flow balance and don't really need a split pattern cam. this lobe is 278 deg@.006, 226@.050, 146@.2, and .340" lobe lift (.544" with 1.6 ratio rockers). for comparison, the flat tappet comp XE275HL is 275 adv, 230@.050, and 149@.2" lobe lift....

http://bulletcams.com/Masters/HRlobes.htm

and an RPM air gap intake will get you another 20ft-lbs of torque down low compared to the M1 single plane, and should match it power wise up to 5500-6000 RPM