The '83 and older trucks had the funky spring hanger pins, front and rear:



They have an oversizes "head" that bolts to the side of the spring hanger, and 18mm shaft and a 14mm threaded end, necked down from the shaft. You can find them at some of the Toyota catalog places, or at a junkyard (also used on the fronts of '84-'85 pickups/4Runners).

Or better yet, hack off the stock front hanger and beef up the front end of the frame and add a new hanger that uses normal bolts (M18x120 is about what you want):

New front spring hanger

You can probably make the new hanger for less than the cost of new pins.