Yes, its now just about a 2x6, maybe a little better but needs a scab on both sides. The 2x4 present is nothing but a filler. Both of the scabs need to be about 6-8 feet long and could be 2x8 or 2x10 properly nailed (lots of nails).

The siding should have at least a one inch gap above the shingles with flashing visible.