do lots of head work. bigger valves, port the heads, gasket match the intake side and put bigger roller cams in it with adjustable cam gears.. put on a thinner head gasket to up the compression. if you want more torque (lower et times) try to find some slightly shorter rods and then also deck the block to keep your compression up. if you do deck it you will have to make sure you get the LIM machined to match the new angle. for the exhaust side i think youll have to make a good set of headers that will scavange well and help bring the VE up closer to 100% maybe even over 100%
that should get you into the low 14s probably even the high 13s
