$big_foo_bucket->{camshaft}   = $other_foo_bucket{camshaft};
$big_foo_bucket->{gearbox}    = $other_foo_bucket{gearbox1};
$big_foo_bucket->{drivetrain} = $other_foo_bucket{the_drivetrain};
$big_foo_bucket->{smokestack} = $other_foo_bucket{my_smokestack};
$big_foo_bucket->{junkyard}   = $other_foo_bucket{_junkyard};

##</code><code>##

@{$big_foo_bucket}{qw[
 camshaft   gearbox  drivetrain     smokestack    junkyard
]} = @other_foo_bucket{qw[
 camshaft   gearbox1 the_drivetrain my_smokestack _junkyard
]};

##</code><code>##

schlep(\%other_foo_bucket => $big_foo_bucket,
    qw[
        camshaft        camshaft
        gearbox1        gearbox
        the_drivetrain  drivetrain
        my_smokestack   smokestack
        _junkyard       junkyard
    ]);