I found a guy that is selling a ford 9 in posi,atm i have a stock 9inch in my 79 bronco.So my question is whats pros /cons of going with a posi?Also can I upgrade the gearing in future they are stock right now will be putting in 4:56 soon...

if you're gonna wheel the thing don't bother with a limited slip, at least get a detroit or a spool. Matter of fact I got a mini spool i'm trying to unload if you're interested

if you did buy it, just remember. Most lockers that fit into the carriers won't fit in a posi carrier. I would buy a Detroit too. Or get Lock Right.

Shop around in the salvage yards... Ford actually put some Detroit lockers in some 9" rears back in the late 60's and early 70's. I had one in my E200 van...

Just pull the whole center section - slap on the gears of your choice and you are all set.

I doubt you will notice any differance driving with the Ford posi. You probably won't notice much of a differance off-road either. If you wheel your truck at all get a detroit. It is worth the money and is like a night and day differance over an open diff or stock posi. If you drive on pavement a lot I wouldn't get a spool. It's too hard on axles if it's in a daily driver. If it's in a trail rig that sees minimal street time, a spool is perfectly fine.