ECU has notheing to do with advance. You may have to change springs, or restrict the total mech advance by welding up the slots. Should be around 34* at approx. 2000/2500rpm, with vac advance disconnected. After you get that nailed down, you can add vacuum advance of around 10/15* for driveability. Initial should be as much as the engine will stand without "hitting against the starter" when cranking.