and another thing, when i look at aftermarket parts for my truck the year range on everything goes up to 86...skips 87...then starts back at 88 and goes up..........why does no one have parts exactly for a 87, im sure they are interchangeable, just something im curious about

the gears that are in that rear end is what is supposed to be in it. you can still count the teeth on the gears to make sure that is the right ratio, but with the power plant that is in your truck doesn't really make the power that you want. and the only other thing that you might do is put in a five speed to off set the rpms of the engine. the 5.0 doesn't have the power like the 4.9 does either in the old days they used the dana rear ends and were not made for fuel economy they were made for work only. the 87's were the year of the model changes and didn't look the same as the year before and then looked like that for the next four rears until 92 then it happened again. I think the reason why it skips 87 and goes to 88 and up is because of the year model changes and all they did was use the same rear ends that they had left over or the next year they started using the 88's

Ok thanks for all your help

so what tranny should I look for that will be a direct bolt on?

I don't know the model numbers on those transmissions all I know is that if you can find one out of a truck that's a five speed with a 4.9 in it then it will bolt right up because the 5.0 and the 4.9 has the same bolt pattern on the hogs head. on the tail end it may have a slide in yoke and your truck may have the u-joint right at the back of the trans.