Front end alignment questions

[67carry-all]

Hi all - just had the front end of my '67 Suburban rebuilt - ball joints, tie rod ends, pitman and idler arms, by a local shop. The mechanic has aligned the front end twice, but there's still a significant pull to the right when driving. The (original) steering box is a little loose and he thinks this might be contributing. I'm thinking it shouldn't matter regarding the pulling - if the alignment is on target, the truck shouldn't pull. Thoughts and feedback? Thanks!