I have an 84 6.2 Suburban. Great trucks. Mine is not 4x4 and is just the half ton but came with tow package. It runs great. Injectors need replaced now at 277,000. Are you sure yours does not have 145,000 or 245,000 rather than 45,000? You can tell by the rest of the body being pretty well used
I paid 2000 for mine.
Still, i just did a 1700 mile road trip in mine in 5 days . Ran like a top 50% veg, 50% biodiesel. It got 20 mpg average and i cruised at mostly 65 and 70 and got as high as 90 on a couple occasions. Plenty of room for cargo and still sleepin in the back at rest areas