If those are the 350 heads you need to mill them to 58-60cc. Are you compensating with dome? Flat is fine. Reprogram trans with springs and wts and alter trans shifts to 5200+rpm . Go with as much stall as you can. Go with as much gear as you will tolerate.
Look in my journal. I have a 305 with 906 vortec heads, performer cam, 3.73, 3000 stall lockup , q jet at first.
I was looking to get my c10 close to the acceleration of the grand nationals of the time. I needed a supercharger.