The two 3yo races not shown in Twenty Grand's PP's above were the Wood Memorial (he won 1st off the layoff) and the Preakness (he finished 2nd)
Judging by all written accounts -- Twenty Grand was plenty best in the Preakness and should have been a Triple Crown winner.
Here is his Preakness chart:
Here is part of the Daily Racing Form write-up saying he encountered major trouble in two different spots:
Preakness winner Mate earned over $300,000 racing in the 1930's. The equivalent of almost $5 million today. Equipoise "The Chocolate Solider" finished 4th. He returned to win all of his next seven races and bank over $338,000 in earnings.
Twenty Grand was retired to stud but proved to be sterile. He had no offspring and was never quite the same when brought back.