I decoded my buddy's 68 FB mustang for him and I cannot remember what "Conventional" means in relationt to his axle. It is a 3.00:1. Is that just traction lock?
I was gonna say "solid" as opposed to independent. Pretty much only trucks have solid axles these days it seems, and some of them (Explorer) don't anymore too.
posi is more of a chevy term and such. ford calls it a limited-slip(2 driving wheels). and a non-posi or conventional would be 1 driving wheel.
Just some food for thought