Small block heads

Swap back to the 318 heads. You killed compression. Reduced flow velocity and made a engine run worse. Your better off pocket porting the stock heads. If your looking to get the car to go fast, 360 (1.88/1.60) valves are the way to go.
Closed chambered heads came along in the late 80's. Look for the heads with the casting numbers ending in "302" for the 318.
Advance wise, I tune the car for highest vaccum. Once I get there, you will notice theres a few degrees where it will stay high on the gauge. Back of the timing until the vaccum gauges drops, then go back (advancing) till it reads highest, not a smidge more. Run and tune with the gas you'll use. Test drive. Make sure it doesn't ping. If it does, you know what to do. Back it off a tad until it stops and then 2*'s.