318WR, on the Edelbrock carb, you said you moved the rod on the pump shot lever. Did you readjust the bend in the rod to deliver the proper amount of movement on the arm?
On the engine timing, 20* initial is a lot. Try backing down 5*'s to start. The small block lines about 35/36 max with vacuum advance, 52 total with the advance hooked up.
Your time and mph are super close to my '74 - 318 Duster. LD4B intake w/hookers and Jegs exhaust.
The gears were 3.21's on a stock tire.
I only spent a few more bucks than yourself.