1963 1/2 ton front suspension

[Greg63]

I am going to begin the replacement of the original front suspension in my '63 with a complete original front suspension from a '70 1/2 ton. All the parts; upper and lower "A" arms, cross shafts, spindles , brake backing plates and front crossmember, have all been sandblasted and painted seperately.
I have all new ball joints and tie rod ends as well as pitman arm and idler arm.

My question is this; Is it easier to assemble all the new parts before I put the new crossmember in (essentially build the front suspension on the garage floor beside the truck and then bolt the entire assembly in) or should I take out the original '63 front suspension, bolt in the '70 crossmember and then start assembling the '70 pieces on the truck?

Greg