383 cam/ setup help

Yeah 140 right in the soft zone.
Too much less would put you in the dog-zone.120 is really doggy.

The way I see it is like this; You can spend money on band-aids or you can spend money on fixing the compression, or you can change the tune, or you can live with it.
--Here are the band-aids; a higher stall TC & bigger gears. Then you will need to change the governor and probably mod the VB. LOTSACASH
--Fixing the compression? New pistons and a gasket set. Or maybe some closed chamber heads.
--The tune; Ditch the cam for one about 2 or 3 sizes smaller.Forget lope, It does nothing for your vehicle. It's a by-product of cam-timing, and if not accompanied by an increase in compression, just softens the bottom-end;as you have found out.
--Live with it. really cheap, but not really an option.

A lopey cam requires a complementary increase in compression, or else it turns into your situation. RRR said it all in post#4
So now if you really are after low end and midrange, the next step is to figure out exactly what cam is in there, to see if the cam is killing your compression or if the chambers are just huge.. If you cant get the timing card or a PN then you will have to do it the hard way.You will need to degree the cam. Thats a lot of work, and really all we need to know is the intake valve closing angle, in degrees relative to a piston BDC. This is pretty simple.Do you need instruction for that?
Once that number is known, and from the cylinder pressure reading and knowing/estimating the cylinder volume, we can estimate the compression ratio, and decide what really to do.
Do you have a clue what your truck weighs?