Zippy did that years ago in his LQ4 tahoe, worked well.

 

port n polished throttle body is also cheap torque increase.

 

As everyone else has said that cam you mentioned will do absolutely horrible for low end off idle torque.

I like the Tri-y header idea... and unfortuntely I also agree you will never get what you want without a Maggie... pick up a Radix for short money and be done.