[big gear head]

If I'm not wrong, the COPO had 16-10 gears and the Moroso had 17-10 gears, 17 teeth on the axle gears and 10 on the pinion gears. The standard Eaton Posi had 18-10 gears. The new Eaton Posi has 17-10 gears, but are not as strong as the old heavy duty gears. The Moroso unit was the Eaton heavy duty unit, but Moroso usually removed the numbers from the case. I've had a few of them apart and I'm pretty sure about the tooth count. Tom's Differentials has sold the 17-10 gears for years, but is currently out of stock. Anyway, that Moroso unit is a pretty stout piece. One of the guys who broke their Eaton at SCR this year could use that to beef up their rear end.