I am already planning on swapping out the front axle for a half ton in order to use a ccp disc brake kit in the front.

have just been offered a 10 BOLT REAR END OUT OF A 67 EL CAMINO WITH DRUMS ATTACHED; the ratio is 3.08. how much hauling/braking capacity would I lose? basically i want to still be able to haul as much as i would in a half ton. i have installed and rebuilt a 283 so i have a bit more horses than i would have originnally i am just not sure what the el camino parts will be capable of.
any advice would be appreciated i am a total rookie.