87 7.4 tbi

[f_ford_custom]

hello all,
I have an 87 R30 CC dually 454 tbi, granny 4, and stock rear. I am about the 4th owner, was told 45k original miles. still had dry rotted 7.50R16s when picked up. I got it as a package with a 32' 5th wheel trailer.

known mods - flex fan, larger oil cooler (I don't think gm put one on that's 1/3 sqft of the radiator), oil pump? (pres NEVER comes DOWN to the scale on the guage-60), and the optional 235/80R16s - It has a gooseneck 2 5/16 ball mount in the bed, w/adapter on TT. custom 3" duals, aftermarket cats

That's about all I know about the truck.

Questions
does this sound right? compression 118-126 - vac @ idle (900) 17"
Is stock TBI worth saving? need TPS, parts store says special 87-88 454 only-will not give back money if 350 tps doesn't work-discontinued 1991
I need it mostly for towing, and gross about 16k
I have a holley 80555c NIB from a mopar that I sold; and several HEI dizzies, would I be better off rebuilding one, and going carbed? I know, regulator to fuel lines, oil press kill switch to fp.
What would be a good engine combo? Economy>Torque>Loud -cruise rpm ~1950@40-2700@70
Rear axle? Dana 70-right? has 14 bolts, cover says dana, ring gear says dana 4.11
Headers or manifolds? entire exhaust is rotted out - emissions exempt co, plus registered at above 8600 GVWR.

I'll think of more, or clarify myself later. I've been up 52 hours, time to sleep. Ill check back tomorrow. Thank you for your time.