[dsraven]

if thinking of a frame swap do one that is common to the truck. the s10 is the common one. the trailblazer will be too wide. yeah, different wheels could help. combine that with different tire sizes and then compare the front end scrub radius and other alignment angles and see what comes up. if you are a mechanic you will know something about these angles. there are also websites which will lay them out visually. when all said and done do something that will be enjoyable and safe to drive. if going with a bigger power unit then also go with some bigger brakes and better steering. the other thing you could do is make a frame table from some scrap I beam sourced from a metal recycler, then build your own frame while still driving the truck as it sits. when done it will be a faster to swap the body onto a completed frame with the driveline already in place.
-grab an assembly manual which should have drawings and dimensions of the frame etc
-do a plan, with drawings and a budget. like a pro shop would do. include the safety items like seat belts and brakes that work. just think how many times someone has stopped short in front of you while driving your modern vehicle and then ask yourself if you could avoid that with the old truck.
-do a thorough check of the integrity of the sheet metal so you don't get any surprises when you take stuff apart and find, for instance, the cab mounts are rotten
-come up with a plan to do the work in a logical manner
-stick with the plan
-have fun doing the rebuild and then driving it after