The only way it works is if Solo found a shortcut for the route. Some nerds on the web say that's what he's actually talking about...
"No! He's not talking about speed! He found a short cut!"
(get back into your parent's basement, nerdling...)
The inference in that whole dialog is one of the MF being a heap of junk, and Solo defends it with a comment that can only be interpreted as a brag about the ship's speed, NOT some shortcut that he, the pilot, found. Contextually, it makes no sense.
All it was was a dumbass script writer (Lucas? Someone else?) not knowing jack.
Now, if you'll excuse me, I need to retreat to my basement fortress of solitude....