[DetroitDan]

I read on Wikipedia that 91 had the best 350, had some internal upgrades to make them last longer. TBI is nice. I happen to disagree with almost everybody on every forum when it comes to body lifts. As long as the body mounts are in decent enough condition, they are a simple and inexpensive way to gain noticeable lift. If done properly they do not fall apart, and there are several benefits actually. Since you are not raising as much of the weight, you are not raising the center of gravity as much, so it is going to be slightly less easy to tip over than a suspension lift. Not that Blazers are very hard to tip over, being short, bouncy and already topheavy.
Another benefit is that you now are able to get in there and clean it much better, which is important if it's used off road.
One of my favorite benefits is the fact that you are not raising the frame, which in many states is where they measure it for legal lift height. 3 inches is a big visual impact, clears a lot of rubber, but is three inches they can't count when they measure you. But I digress, the real reason for wanting to keep the frame down within reason, for me anyway, is to maintain a usable towing and plowing platform. Not like you're going to tow much with a K5, but I have a plow on mine, I have a 4 inch suspension which doesnt bother it much being that it's an old adjustable height conventional plow, but many newer plows are sensitive to mounting height. My old dually had a body lift, rear air bags and torsion bars adjusted up to fit 33s, and my hitch and plow were at their absolute maximum upper limit.
In theory suspension lifts may be simpler, less bolts to remove and replace, but I've done numerous of both kinds, body lifts are quite simple, as long as the mounts are not rotted away. I've done a bunch of body lifts on the ground in the driveway, with wrenches and a jack. I did a spring lift once that way, it's really tough if you don't have a shop with a lift. Used to be that body lifts were far cheaper, but I have seen the price go way up over the years. But you will maintain facotry suspension geometry, can keep your shocks and steering. I just put 4 new lift shocks and a dual steering stabilizer on my 91, spent about $250 with a ton of comparison shopping to get the best bargain. If you go suspension lift you must replace the shocks.
So, to sum it up, I think body lifts are a good place to start.