hotrod ,I just got the duster email and pix returned . you give me a *** up email address? if ya didnt get the duster and the dart call me 772-807-9009 if your interested, I just spend 45 minutes sending you pix and info f that.  

Wow, lets keep it simple, first you won't beat a dynamic converter period its simply the best value for the money out there especially the 9 1/2".
Your already have most of what you need, so why would anyone go telling you to replace half the motor, like pistons etc.
A bodies are light, go with the 4.10/4.30 max gear its all you will need, 28x10.5 mickeys slicks.
As far as the motor the cam is going to be the secret, I would think a hughes solid in the 244 range at .050 with a lift in the .570 range would get the job done.  
You will need adjustable rockers and the right valve springs, if your heads are not set up for this much lift, then consider the mopar .528 solid,  I know you will go 11's, but I don't think its enough to get you into the high 10's.
However this is a great street strip cam and you would be very happy with its bottom end torque.
good luck  

Low 11s in a 440 A body shouldnt be that hard.

The 284-.528" may work but I think it would come up a little short, I would step up to the 296-.557" solid.
M1 single plane with a 850 double pumper on top.

I didnt see mention of what headers your using but I would look at a 1-7/8" tube which means either Hooker fender well or  ProParts semi fender well but the TTI 2" under chassis would probably be ok.

For converters I like Turbo Action or ATI but theres plenty good companies out there, Dynamic, Ultimate Converter Concepts, PTC ect.

I think 4.30 gears and a 28" tire should get the rpms up were they need to be.  

with the 296* .557 a 4.57 gear would be optimal and probably nesessary with the diameter tire required to get that thing to hook.
.528 CAM with 1.6 or 1.7 rockers will get you there as well as long as [for both] the heads are matched [flow wise] to the cam.  

You think low 11s with the .528"?  Maybe.

I know of a Dart Sports, 451 (400 block 440 crank) Ported Eddy heads, M1 intake, a 4500 series Holley and a MP.590" that goes 9.90s