Conversation Between ultraranger and rbmead

I don't recall the actual length and they are installed in the 9-inch rear end housing under my truck but, they're the same length as the 28-spline axles they replaced. If the 31-spline axles are from a '68-'72 F100 9-3/8" rear end, they will be the correct length to fit a '68-'72 F100 9-inch rear end housing.

There is a 3,300# 31-spline axle with a 1-17/32" axle bearing journal (from a 9-3/8" rear end with an open differential) and a 3,600# 31-spline axle with a larger 1-5/8" axle bearing journal (from a 9-3/8" rear end with a Traction-Lok differential). I have the 3,300# version in my truck.

sorry to bother you.
I just wanted to ask. on your 31 spline axles. what is the length? the ones i pulled out of mine are 30 1/8 28 spline.
the one I found on that Car.Part site. telling me the 31 spline he has are 29 something.
again sorry to bother you, im just axle dumb.