I have an Edelbrock adjustable timing chain on my 360, and the timing cover off...if I wanted to improve the lower end, woudl I advance or retard that cam.

The timing chain alows, 3 degree of adjustment either way.

Should I worry about the valve to piston clearance (I am running the stock dished pistons)?

Here are my current specs:

74 Cuda with a 360,
Eddy torker II intake,
Eddy torker Plus cam,
The specs are as follows:
@050 Int dur. 222 , Ex dur. 234
Lift Int .447 Ex .450
Intake Centre line 107 Ex centerline 116.
About 9:1 compression.
Holley 750 vac secondary carb.
Dizzy has been recurved, running 20 initial, 38 total all in before 3000.

727 with stock converter (I know -its on the list!)
8-3/4 with 3.22s

Thanks!