I'm rebuilding a 1998 350 from a silverado. I may have gotten the main bearing caps mixed up and i'm wondering what the sequence is for them. Each has a number.

 

You're screwed, they don't have anumber identifying where they go, just an arrow pointing to the front.....the numbers say nothing about their position. If you have them mixed up there's no fool proof way to check which one goes where, a bore micrometer may get you the correct positions if they mic out different enough and check the transition to the block, see if it's smooth, in the wrong spot there should be a couple of thousands difference/ Also check the imprint on the block and the cap mating surfaces, maybe you can spot which one goes where (with a flashlight.

If this won't help, you're looking at a line hone.

 

If you get a dial bore gauge you can figure it out. The housing bore will be out by a few thousandths if you have the wrong cap in place. If it's a 4 bolt block it's pretty easy to figure out #1 and #5