31 inch tires on a 89 s10 blazer

i was told that u can put 31's on a blazer with the stock rims only add a leafs on the rear and tightening the front torsion bars

Most 4x4 blazers came with 235/75R15 tires which are just about a 30" tire. Most 31" tires are just under 31". (29.5", 29.8")

You can do the set up you mentioned. Not many people will agree with adjusting torsion bars that much.
A body lift is another option. Its under $100.