for (my $i = 0; $i < scalar @arr1; ++$i)
{
  my @garr = (@$arr1[$i], @$arr2[$i]);

  # do main processing on @garr here.
}

##</code><code>##

for (my $i = 0; $i < scalar @arr1; ++$i)
{
  @{$garr[$i]} = ( shift(@$arr1[$i]), shift(@$arr2[$i]) );
}