Well for starters, im currently in Afghanistan and cant look at my rear axle....I have a ford 9inch that came stock with my 74 f100 4x4, also came with a 360ci and 4 speed trans....is there any way to find out what spline count the rear end is with out me waiting to get home and pulling it apart?

 

Long shot, if the axle tag is still on the rear it can be decoded to find out which axles you have. Someone would have to crawl under the truck to see if the tag is still there and then read what the tag says.
Other than pulling an axle, thats about the only way.

 

you are USUALLY safe with looking at the end of the axle where the wheel studs are. if there are 2 circles you have 31 splines but the only 100% sure way to know is to pull an axle. Here is a link to the 2 circles :
http://www.kevinstang.com/oct10.jpg

 

That's not true I have several 28 spline axles with the circles/holes. Pull an axle is the only real way.

 

I'm with Wiz ... pull it.