But they are fun questions
. No harm in talking about it.
Rafa would not be able to hit his forehand with Borg's racquet. That racquet's weight was 16 ounces, because, as Deuce says, it was specially made for him. Because Borg strung his racquet at 80Lbs, he needed three extra laminations on each side or the racquet's head would crack under the pressure. So, try to imagine Rafa hitting that forehand with that much weight. I say his elbow would break soon after the first set.
Borg and all those greats were also smaller than the current crop. They were around the 5'10" mark. Lendl immediately made the push to larger champions as he was about 6'2". But what Borg had that separated him was his speed and stamina. Remember, Borg resting heartbeat was 36; basically half of a normal human being (Miguel Indurrain, the spanish cyclist, was 30).
And, apart than motor sports, no sport has changed equipment as much as tennis. I believe I have played with all kinds of racquets, and the technology today is insane. I played with the Dunlop Maxply, hit with the Jack Kramer, played with the T-2000 (actually, the T'3000), the Yonex R-22, the Maxply 200G and the family of Wilson's Pro Staff and the racquets make a lot of difference.
So, I say: wood racquets: Borg beats Rafa at RG. Modern racquets? Rafa, 8-6 in the fifth.
Borg was special too.
(Slick, 1985 grass? McEnroe beats Roger at Wimby. 2005 grass? Roger turns it around).