I receive queries for novels across category and genre that can be described as long ass.
It's a technical term as you no doubt inferred.
Long ass novels start at 200K and go up from there.
More than one unhappy writer has told me that they need every single word.
That's almost always not the case.
How do I evaluate? If can pare 10 words out of your 250 word query, I know I'll find too many words in your novel.
And while I'm cognizant of the lovely moment in Amadeus when the Emperor tells Mozart there are too many notes, you aren't Mozart, and I'm not (as yet) the Ruler of All I Survey.
So if you want me to consider a long-ass novel your query better be as taut as a blood bank dwelling mosquito.
The other thing you need to consider: if your novel is twice as long as most trade novels
(ie 170K/2 = 85K)
you're asking me to take you on instead of two other not-long-ass novels.
Instead of signing two novels of 85K each, I'm signing one.
Which means I think about whether I can get enough money for your book to make up for the lost income of the one I'm NOT going to sign.
Opportunity cost is what it costs to NOT do something.
And it's measured in dollars and cents.
A long ass book means you're asking for a lot of reading time, and editing time.
It's also asking me to take a bigger risk than normal.
That's one of the reasons word count can be a deal breaker.
I'm not saying don't write a long book. I'm saying understand why you're going to be scrutinized much more closely for taut writing than other books. And why word count is a deal breaker for most agents.