Some 5.9 roller cam help from y'all please

Here is my direct torque cam experience in my old 351C in a Ranchero. (NA, carbureted engines of this ear work pretty much the same...)

Your use description if very close to this case. Here is info So you can compare to your planned use:
- It was a car that would pull hard from below 2000 RPM and to over 6000 RPM.
- I used it for old time street drag racing up in the old days in Chambersburg PA (a cool place to be a gearhead in the 70's).
- It also was my daily driver for many years and was a good performer in mountain driving with the wide RPM range.
- 19 mpg on the interstate at 65 MPH. No overdrive or locking TC to help.
- I flat-towed a 2600#rally car all over the eastern USA with it with spare parts and tires in the bed.

Setup:
- Used the stock TC and C4 trans (kinda like a 904), and the rear axle was 3.08.
- Vehicle weight was around 3400 lbs.
- A 10+ SCR helped the low RPM torque too so that added to the cam used at the bottom end. I don't know if you plan to have that high a SCR.
- The mildly ported 351C 2 bbl heads heads breathed significantly better than the Mopar stock equivalents of the day. Your EQ's are even better than the 351C 2 bbl heads.
- Used 1.78" headers with long collectors for the low end, and the older Torker single plane intake.
- The heads and intake/exhaust made the engine better at high RPM than you would expect for the cam used.
- 600 cfm Holley vac sec 4 bbl, model 6619 calibrrated from the factory for improved economy.

CAM USED:
An old fuel crisis era Crane hydraulic economy cam (HE grind). It is somewhat like the Lunati Voodoos and embodies what is normal in a torque/economy cam: short durations, as high a lift as you can get with the usable cam profiles, and wide LSA.
Duration: 190/200 at .050" (for real!)
Lift: .445"/.471" (This takes advantage of the higher 1.73 rocker ratio on the 351C)
LSA: 114*
Cam timing as built: Installed straight up
Advertised RPM range: 1600 to 4200 RPM (Keep in mind that Crane advertises RPM ranges conservatively and for stock breathing engine parts. The same cam would probably be advertised as 1300-5000 RPM by most other mfr's)

In the above engine, the top end was enhanced by the better breathing parts (mild ported head, intake and large header). You look to have roughly equivalent parts with the EQ heads, and headers and good intake, so any RPM range will likely be well extended above the advertised numbers. So if you had a 4800 RPM max advertised cam RPM, I'd expect it to pull well up into the upper 5000's range or even over 6000.

The bottom end above was pretty much set by the cam and the larger breathing parts probably compromised it by a few hundred RPM at most, based on actual driving experience. I think you will end up the same if you keep the minimum advertised cam RPM range down in the low 1000 range.

In a Mopar, you can't use quite such a low duration cam with hydraulic lifters as the rocker ratio is 1.5, not the 1.73 of the 351C. So, you need to go with somewhat higher durations than this old 351C cam to get into the .450-.500" lift range. But staying in the 200-212* at .050" range is the highest I would go in your application. Keep the LSA to 112 or greater and go for as much lift as you can without too much risk for lobe/lifter damage from too high contact pressures. A roller cam will get you a lot closer to this type of profile.

BUT, if you have to have the lope, then more duration or narrower LSA. (They kinda go together...) Expect less economy and a more compromise of the low end torque.

BTW, we did not have enough letters in the alphabet to spell 'dyno' back then, so sorry, no dyno numbers. HP should have been in the 300-325 HP range and torque up in the 350-375 ft lb range. I never had it on the strip but it ran low-mid 14's based on my own rough timing in a measured 1/4 mile.

Sorry for the long post; I just wanted to be complete. Hope it helps! Your brother story is funny LOL