Skip,you don't want to mess around with any bolts,you need bolts that are made for steering gears.Here's a link to some bolts on ebay,there for Camaro and Chevelle they might work
SkipFIx; The bolts are 3/8, grade 5 bolts. The length of the bolts ( not including the head) is 3 5/16. The head is about 3/8 of and inch thick, so you can get a wrench on them. There also are (3) 3/16 thick washers, that go on them. Hope this helps you out. Skip