A few simplifying asumptions made here:

duplicate lines don't exist or don't matter

machine generated output so white space matches

case is important

Appart from the first, these are easy to fix (exercise for the reader?).

Note that just file index information (from tell) could be stored as the hash value rather than the remainder of the line and the lines reread as required.

use warnings;
use strict;

my $Fn1 = shift;
my $Fn2 = shift;

die
  "Usage:\n" .
  "hash4Ans <file1> <file2>\n\n" .
  "file1 and file2 are the files to compare\n\n"
  if ! defined $Fn1 or ! defined $Fn2;

my %File1;
my %File2;

open (inFile, "$Fn1") or die "Unable to open $Fn1 $!\n";
while (<inFile>)
  {
  chomp;
  my ($Key, $Tail) = /^((?:\w+\s){4})(.*)/g;
  $File1{$Key} = "$.:$Tail";
  }
close inFile;

open (inFile, "$Fn2") or die "Unable to open $Fn2 $!\n";
while (<inFile>)
  {
  chomp;
  my ($Key, $Tail) = /^((?:\w+\s){4})(.*)/g;
  $File2{$Key} = "$.:$Tail";
  }
close inFile;

my $Key;
foreach $Key (%File1)
  {
  next if ! defined $File2 {$Key};
  
  my ($Ln1, $Tail1) = $File1 {$Key} =~ /(\d)+:(.*)/g;
  my ($Ln2, $Tail2) = $File2 {$Key} =~ /(\d)+:(.*)/g;
  print "Match in line $Ln1 from $Fn1 with line $Ln2 from $Fn2:\n";
  print "$Key$Tail1\n";
  print "$Key$Tail2\n";
  
  my ($Words1) = $Tail1 =~ /(?:\S+\s+){3}(.*)/g;
  my ($Words2) = $Tail2 =~ /(?:\S+\s+){3}(.*)/g;
  
  print "Note: Tailing word mismatch in previous pair.\n" if $Words1 n
+e $Words2;
  print "\n";
  }
  
print "Done.\n";
[download]

word word word two    2 1.2 -2.3 apple   six seven eight nine
word perl word five   5 1.2 -2.3 grape   six seven eight nine
word word word seven  7 1.2 -2.3 lemon   six seven eight nine
word word soil three  3 1.2 -2.3 orange  six seven eight nine
word word word four   4 1.2 -2.3 onion   six seven eight nine
word word word one    1 1.2 -2.3 five    six seven eight nine
word word word six    6 1.2 -2.3 fig     six seven eight nine
word word word eight  8 1.2 -2.3 sausage six seven eight nine
[download]

oink word word one    1 2 -2.3 five    six seven eight nine
word oink word two    2 2 -2.3 apple   six seven eight nine
word word word three  3 2 -2.3 orange  six seven eight spoon
word oink word four   4 2 -2.3 onion   six seven eight nine
word word word five   5 2 -2.3 grape   six seven eight plug
word word word six    6 2 -2.3 fig     six seven eight nine
word word word seven  7 2 -2.3 sour    six seven eight nine
word oink word eight  8 2 -2.3 lemon   six seven eight nine
[download]

Match in line 7 from data1.txt with line 6 from data2.txt:
word word word six    6 1.2 -2.3 fig     six seven eight nine
word word word six    6 2 -2.3 fig     six seven eight nine

Match in line 3 from data1.txt with line 7 from data2.txt:
word word word seven  7 1.2 -2.3 lemon   six seven eight nine
word word word seven  7 2 -2.3 sour    six seven eight nine
Note: Tailing word mismatch in previous pair.

Done.
[download]