alignment trouble

left the allignment shop with my 66 after watching the guy put the settings rite on the money, got home and was checking it out when i noticed the front tires were toed way out, so drove back to the shop and put it back on the rack and reset everything,drove home and still the same thing only not as bad this time. all parts have bin changed a while back but theres not many miles on them,they looked tight when he inspected them. anybody else have this problem? whats going on?