disapoining et

Took my 72 duster to the track for the first time, I was a bit disappointed to say the least. Mabey my expectations were to high, but I feel like my combo is off.

Specs.
1972 duster
383 hp block
906 heads, bowl work and gasket match
1.6 roller rockers
Comp cam 280h grind
3000 10inch turbo action converter
3.55 gears
26 tall street radials

Best result of the day
60 foot- 2.25
330 et- 6.20
1/8 et-9.47
1/8 mph- 75mph
1/4 et- 14.69
1/4 mph- 93.76
Around 5200 rpm

After talking to my engine guy his suggestions, while keeping it treatable are
Manual valve body
Moar performance leafs(replace worn out stock ones)
Gas shocks to replace the air shocks
Slicks 8x26 for track days
M1 intake to replace eddy performer.

I would like to see low 12s. Mabey someone has a similar set up they can share or some ways to get to where I want to be.