My mods are in my sig. Black smoke is not normal for these trucks, it may suggest that it is not getting enough ait. Filter & air intake first thing to look at. Then check waste gate operations, linkage / selonoid. My truck will only put out lot of black if I realy put my foot in it and accelorate hard under load. Check out this site with a search for your problems , ask the right questions and someone will usually have answer. I have gotten a lot of hel[p over the 5 yrs. I have had my truck. I would have gotten rid of it years ago without the help of many people on this site. Good luck.
'95 GMC K2500, "Bullet"Ex. cab short.4X4, 377,000kl on truck, 177,000kl on AMG engine, auto. 3:73 Ltd. slip, FSD remote mount, OPS relay,AFE air IN, Kennedy 3 1/2" OUT . '83 F250 HD3/4 " Robert The Red Ford"4x4 460, 3:55'posi . 2005 GMC : G WHIZ" crew short box, 5.3, 4:10. , '88 Bronco II 4X4, '95 141,000kl Ford F150 EX. short box, '92 "Toy" 4 runner 273000kl ,'63 Mercury 45000miles !!!! Auto insurance co. is my mistress !!!