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
Mopar 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. Maybe someone has a similar set up they can share or some ways to get to where I want to be.
ok I will give this a try without getting bashed too hard,first thing I would do is get rid of the gas shocks and get a pair of shocks for a 60s station wagon,preferably the old OEM ones,then take the clamps off behind the rear wheels and put another one on the front,then put at least a 4 degree shim under the spring perch.(you can get these at napa or a place the does truck front end work)and while you're under there take your pinion snubber out and throw it away you don't need it any more you're putting big boy pants on that thing now!..that should pretty much get you hooked..if your timing is around 38 I think you're in the ballpark and im think you have spring kit in your dizzy right?any ways after a hard run pull a plug and see where your timing is at (to do this look at the I will call it the wire that comes up from the plug with the bend in it,)your timing mark will show there.and It should be in the middle of the bent piece if its higher back it off a little bit if its lower ad some to it.but it will show you where it wants to be.and I think I would try that intake just because I never had one.and I would think you will want to be in the 70s range for jetting (rusty ratrod would be the one to ask for that.or anything else as far as that goes)and if you're running the blue holly regulator they will not flow over 90 cfm's of fuel if more is used you will need two..with separate lines.and the converter should be flashing at least 1000 rpms above were the cam is starting to work.have you tried flashing it to see where it comes in.you do that in high gear if you have a manual valve body in it.I feel this motor should run In the 11 et. range with no trouble and still be a drive any were kind of car.......just trying to help ya........Artie