5.9L Magnum questions

Well, I was lucky enough to get my hands on a decent 1998 5.9 Magnum core locally. Supposedly out of a Dakota R/T. Stripped it down that day and was pleasantly surprised at it's condition, considering it supposedly had 100K plus miles on it. Virtually no ridge in the cylinders, and they still had crosshatch in them! Inside was very clean, no chunks or gunk inside. Heads were clean also. Had a couple broken studs, but I was able to extract them without any damage. Haven't got to the bottom end yet, but it spins free and and if it looks like the top, I'll be happy.
My goal for the motor is to do a "best bang for the buck" build I can while creating a reasonable amount of HP/TQ. I realize that everyone's definition of "reasonable" is different. Just hear me out...you can take turns kicking me in the nuts later.
Motor is going in a 66 Barracuda that has the original 273/904 in it. Want to transfer all the 273 parts (timing cover, pulleys, EX. MANIFOLDS, etc.) to the 5.9 if possible and keep the 904 behind the 5.9. Will try to be more specific below- not necessarily concerned with any hard numbers right now, just tell me if the info below makes any sense. I know you guys have been at this WAAAYY longer than I have, that's why I came here. All comments welcome.
Here we go- pretend I have a 20 yr. old's wallet, because I pissed away too much money on my Belvedere ll previously. (I'm 66 and still working. American dumbass).

1. Hone/re-ring motor with stock pistons. Would like to improve CR if possible. Deck/square up block, cleanup cut on heads, and .027 Cometic gasket? Maybe worth .040?
Pistons "in the hole" as follows- only checked the corners- #1 .045, #7 .044, #2 .044, #8 .051
2. Check/mic main and rod journals. If clean, new bearings and re-install.
3. New high volume oil pump. Double roller timing chain and gears.
4. Intake- Edelbrock Performer...or maybe even the Chinese version. Have one on the 5.2 in the garage, haven't run it yet. Looks well made and machined though.
5. Carb- something in the 650-750cfm range I would guess. Not partial to any particular brand.
6. Heads- stock, fresh valve job, stock 1.6 rockers, cleanup cut, home ported ala Charles Servidio videos. Fingers crossed.
7. Cam- see attached pic. I intend to go to Oregon Cams and get a regrind based on the Hughes cam numbers shown. If anyone can give me a yea/nay on this choice, or provide a better grind for this combo, I'm all ears. Required springs, too. 5500 rpm max should keep me out of flying parts territory, and most of my driving will be midrange anyway.
8. 3000 stall converter, manufacturer unknown at this point.
9. 3.55 SG in rear. I have a 3.91 in the Belvedere...and a 5 gal. gas can in the trunk. You know, just in case...
10. Exhaust- this is where I'm a little stumped. By that I mean efficiency versus $$. The headers I WANT are $1000+. The manifolds I HAVE and I know will fit, are FREE. Question is, what is the loss in efficiency/fitment between the Doug's (or any) headers and the iron manifolds? Can I modify the iron to improve flow? Dunno. Yes, planning on using a header flange on the drivers side if I use manifolds.

I'm sure I forgot about 100 things, but please feel free to remind me. Best I can do on a Sunday morning. Any and all responses will be considered to get me to the most efficient, economical build. Thank you.

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