If its for a 31 spline pair of axles its a great price, for a 28 spline its a little high.Ford used the 28 spline axles behind the 289 HIPO engine and 390 GT's, so they felt they were good enough. For extreme use and high torque applications- such as drag racing (ie 428CJ and Boss cars) the 31 splines were basically required if things were going to hold together. One other advantage for 31 spline axles- you can find alot more 31 spline centers (they were used in alot of truck over the years)- especially posi's (trac locs etc.).
Ok that's what I figured. So if I am not going to be throwing too much at it, or taking it to the strip, a 28 spline rear is good? I am having my 3rd member made for me so that isn't a concern. I have a good lead on an 8" housing for 30 bucks, axles for $100, and 3rd member fully rebuilt drop in for $400 with 3.50:1 gearing. I am looking at around $550 bucks for a rear minus brakes pretty much brand new. Man I wish I could find a complete unit from the right year with the right gears. I bet I could save some money.