I am getting ready to put a 383 together for my 85 D100. The truck will be used as a daily driver during the summer and should weigh about 3900 pounds with driver. I would like the truck to run 12s and use some of the parts I have laying around collecting dust. Here is what I have to work with.
.030 over 383 with flat top pistons .030 in the hole with no valve reliefs. It should be about 8.5:1.
346 heads mildly ported with 2.14/1.81 valves
Factory rockers
Weiand action plus intake
750 Holley
1 3/4 headers
727 trans with shift kit
TCI Breakaway torque converter
8 3/4 rear end with 3.23, 3.91 or 4.10 gears
I still need a new camshaft and would prefer a hydraulic flat tappet. Do you guys have any suggestions for a good shelf cam that will help me reach my goals and work with the pistons I have? Also if you see anything that might not work let me know and thanks in advance.

Here is a picture of the truck it’s going in. It’s the one towing the trailer.

If it's going to weight 3900 and run a high 12, buy a nitrous kit for it.

One of the (2) Summit house brand cams. 3.23 gears.

I think going high 12s with the parts you have will be tough to do. I could be wrong, but I bet the TCI breakaway is similar to the factory hi stall. 383s need some converter. This would be much easier with a 440 but I realize you already have the parts. Big stall ,big gear and big cam in the engine you have might reach your goal but will take away some of the streetability. Depends on what you can live with. As Moparpollack suggested, you could put a kit on it.

4.10's, better juice it.

The larger of the two summit cams doesn’t seem too bad. Do you know if these are a quality piece? I wouldn’t mind more lift, but I’m not sure if I would have clearance issues.

It probably will get a small wet kit too. Lol

i have used a few with no issues.

I have one, not yet used. Several people have recommended em with no issues so I pulled the trigger on one for a mild build. Not sure if you have enough P/V clearance or not but .030" IS pretty close to the top.

The lobe separation angle and lift and duration at from 30 degrees BTDC to around 15 ATDC on the intake valves makes the valve get close to the piston tops A cam ground on a 105 LSA with 260 degrees @.050 installed at 105 LSA will have less V to P clearances than the same lobe put on a cam with 110 LSA installed at 110 on the intake lobes in the same motor

It doesn’t look like a 12-sec package to me, but you have the parts and the plan........ and it will run what it runs.

I built a 383 almost identical to what you are planning. I used a Crane cam powermax cam with .467/.494 lift with 114* LSA. It was in an 86 short bed truck with 3.23 or 3.55. It ran 15.0.

Yes: That is what I would expect. Like I say 4.10's, juice it and get a convertor.

It looks like my short block is not as good as I thought. The crank needs to be reground, so I am going to zero deck the block and mill the heads to get the compression up to 9.5:1.

It'll be hard and likely not possible to get to where you want to go with what you have, and the overall goal/usage for the truck.

You'll have piston to valve to clearance issues with any cam that has 12-second-potential on a zero deck flat top piston in a 383

The combination of short stroke and long rods (n = 1.88:1) means the piston is very close to the deck around TDC which limits lift. This narrows your choice of which cam has enough .050" duration (like 240) but low lift or wide LSA.
Your static CR is low for any hot cam.
Your deck clearance is too loose for good quench/turbulence.