What ratio does that give me? This is on a Blazer and I thought it had shorter rear gears than that. Something seems off, but I just got the Blazer from someone else and maybe it's been tampered with. What gears are that tall?

sounds unlikely - but if it's accurate, then two turns of the driveshaft to one turn of the wheels is a 2:1 ratio. maybe your transfer case or trans has a really low first or crawl gear.

Is the rear in the blazer a posi or locker? If its a single track, and you held one wheel I believe the wheel that is free spins twice as fast (at least that's what I heard, never measured it). In your case that would be around 4:1, which makes more sense. I don't believe they ever put gears in that were less than 2.56:1 and those were probably not available in a blazer.

Tom

A differential will produce 720° of rotation of the wheels for every turn of the input times the gear ratio. If one wheel is stationary, the other wheel will rotate the entire 720°. If both wheels rotate in unison, each will rotate 360°. If you rotate one wheel 180°, the other one will rotate 540°, etc.

2.56's were indeed avalible in full size trucks, and common in 4x4's [go figure] Most trucks got 3.07's though....