The phrase "a tremendously good" is correct and usable in written English.
It can be used to emphasize the high quality or excellence of something.
Example: "The movie was a tremendously good experience that left a lasting impression on me."
Alternatives: "an exceptionally good" or "a remarkably good".
"I have a tremendously good relationship with the manager and my team-mates.
But sports, when they are play, can be a tremendously good thing for boys".
It would be an exaggeration to say she looks bad-tempered, but she doesn't look in a tremendously good mood.
He was a tremendously good raconteur, and I think I inherited my gift for storytelling from him.
Water is a tremendously good conductor, so all penguins have to be designed not to lose serious body heat when swimming".
Alberto Vitale, her longtime boss as the chief executive at Bantam Doubleday Dell and later Random House, often described Ms. Grey as a "tremendously good editor".
And they have a bunch of tremendously good and effective reporters: some on the national-security side, like Devlin Barrett, some at the White House, like Phil Rucker and Ashley Parker and Jenna Johnson, who really understand Trump.
And there is one thing that I know, after having worked with Governor, now President-elect, Bush for the last 18 months, and that is that he is a man of tremendously good judgment, with strong values and principles.
It might only be available to lease in limited numbers in only a few areas, but the Honda Fit EV certainly has one thing that's tremendously good about it: an official EPA rating of 118 MPGe and a range of 82 miles.
A few minutes later, the 23-year-old N.B.A. superstar LeBron James lauds Crosby's revival of the Penguins and calls him "tremendously good at such a young age, just like myself".
According to Bruce Pandolfini, executive director of the Manhattan Chess Club, & a U.S. National Master, the players at Washington Square Park are tremendously good.
