Big Block Edelbrock limitations.
He really didn’t give enough info to even start in the first post other than saying they were out of the box heads. Lighter cars than yours but Thumper that rebuild carbs has gone 9.80’s with a ported set. A friend of mine in Pa has gone high 8’s in the 1/4 with his ported Edelbrock in a lightened Duster. It all comes down to the right package and how much you want to spend.