i found a 14 bolt at the junk yard today its on a 79 C20 i think it has 4.11 gears but i cant tell if its a FF or a semi...i was wondering if it would work on my 90 K5....

 

You would have to measure the spring perches and the over all widths. I can get those measurements for you today if I can remember. I have a 14bff out of an old heavy 3/4 ton that has the proper spring perch spacing and width for the K5.

You can tell if it is a FF by looking at the wheel hub. If you have 8 bolts in the center of the hub like the picture below, it is a FF. If not, it is just the 14b.

This picture shows the end of the axle with the axle shaft itself removed:

 

it has 8 lugs i made sure i counted that....it has 4.11's in it and they told me 125 for the whole thing

 

I am not talking about how many lugs it has. For it to be a full floater, the axles shafts themselves are bolted onto the outside of the hub. Here are some more pictures to go along with that one I posted above:

What I was talking about is that extra set of 8 bolts holding the axle into the hub.

Oh and it needs to be 42.5" center of spring perch to center of spring perch for a "bolt-on" installation. My axle is ~66" wheel mounting surface to wheel mounting surface.

 

thanks....thats some good info...so i think i might go measure it today...but if it all works out how hard do you think it would be to convert the breaks to discs...and could i still run my 35's...oh yeah and yes it had those 8 lugs also....if it measures out i think 135 is a good deal

 

You can remove the drums and install the same rotors from the front, get some brackets which are made by quite a few different companies, and bolt up a new replacement set of Cadillac Eldorado rear brake calipers to retain the parking brake functionality.

Most of the bracket kits have spacers. I like the ones that are bent properly. HERE is one, but it does not have gussets in the bends like I would like to see. It is fairly economical though. Aside from the use of spacers, THIS KIT is nice.