It’s not a bad idea at all to get a pre emission truck but downtime is something you’re going to have to figure out.
Unless you buy one that is in pristine condition from a sole owner operator that kept up with every single solitary thing on that truck, you’ve got two choices.
Choice number one is that you stop and fix everything, and I mean every every every little thing on that truck and every big thing on that truck before you start, or you fix it as you go which is going to lead to downtime.
I am not trying to dissuade you at all, but do not ever ever underestimate the number of things that a truck that is that old, no matter how pretty it looks, can need.
And whatever you think it needs before you buy it you need to seriously make a multiple of that number because it’s going to always be more than you think and take longer than you think.
Plan for the you-know-what hitting the fan, and you’ll always be fine.