sheet metal intake

If you cut the manifold (red line) and make you adapter longer (green line) you will reduce the angle needed.
ab-manif.jpg
 
I do not know what RPM you are looking to turn. But making the runner longer will lower the tuned RPM. Here in example two the angle is a little greater than example 1 but less than your angle and it keeps the runner length just about original. Purple line.

ab-manif2.jpg