what to do with my (her) rear end??

[59weasel]

ok so they daughter and i are at the point of changing her rear end out in her '66.

going from a 3/4 ton axle to a '87 10 bolt.

my question is how do i deal with the different size of axle tubes? as the U-bolts go through the trailing arms close to the axle in it now, the 10 bolt is alot smaller tube... how will this work? it seems like it will be very sloppy? after welding new axle perches on and re-bolting them down with new U-bolts will this be sufficiant enough?? just seems like there will be alot of room between the U-bolts and the "new '87" tubes??

anybody done this and have some answers for me (and her)?
she thinks i know everything but you guys have helped me about 85% of the decisions i've made on hers and mine!!

thanks !!