Having been around diesels MY whole life, repairing them since I was old enough to hold a wrench and running them (in tractors, Internationals mostly) since I could walk, I can attest to the fact that a strong engine doesn't need to smoke to have power. In fact, since I don't drive my diesels at 8K feet and work them ******* farms and the roads hauling perhaps more than I should be, I can tell you that I don't necessarily need a turbo and that smoke means squat.
Most of the Internationals (tractors) on the farm are NA and will do just about everything the turbos can, maybe just slower and they require less fussing with and monitoring. So working them hard all day is less stressful and as long as the oiling, cooling and fueling systems are working properly.
The beat up farm truck you see in my picture has a stock 6.9 with the pump just timed correctly, intake air improved and exhaust freer yet controlled to keep the po po from hassling me. And still like most other IDI owners I have hauled a LOT more than what the truck is rated both on board and on a gooseneck. I won't win any race, beauty contest, or be the quietest truck around, but I know that I didn't have to spend $30K to get a truck that will work as hard as I need to. And if I want more out of it, it's there if I want to add a turbo and change from the stock IP and injectors.
When I was 17 I wanted Cherry Bombs on my vehicles so my buddies would take notice of me, now I only worry that the exhaust is free flowing and loud isn't necessarily the answer to free flowing just like blowing black doesn't exactly mean you have power to spare. What it means is that you have fuel to spare, and that you will get noticed by your buddies and probably the police who will bother you about checking for dyed fuel, excessive smoke/noise - whatever. And like mentioned before, with more fuel than air you can possible melt some components that will leave you with a pretty boat anchor.
What I am getting at is, the IDI diesel was designed to work all day without complaining unless it's oil is neglected to be changed at decent intervals and with quality fluids. They don't have electronics to govern the fuel supply, engine speed, timing, or even the noise the engine makes so that some so called "endangered animal" doesn't lose sleep and lose the desire to reproduce and hang out in your backyard and annoy you. If you want the ease of building power with just a chip replacement or program download/upload, then you're going to want something a LOT newer.
The point I am trying to make is although a stack blowing some heavy black particulate into the air looks tough, it's just blowing it's load without pulling any more load than a less smoky emission. I think it's cool that you want to run an old machine and work it hard, and dammit - hard work it will do. But, if you're looking to run an old machine and compare it with (let's just say) a Duramax, even though you have two diesel engines sitting side by side you are essentially putting an old, well, 766 International farm tractor next to a newer 4640 John Deere. They both do the same thing, one just does it in a rough, lumbering and loud way and the other in a more refined, quite and comfortable fashion.
Boiled down, smoke is easy to get and so is dependability. But you can't get them both by guessing or doing it cheaply. And you will get noticed, just not always by those you are looking to impress.
Don't feel that way. There are a lot of youger members and we want you guys to hang out and learn from the older, more experienced members. There is a huge wealth of knowledge here on these IDI's. More than anywhere else on the web. 
