A friend turned me onto the the belted Z-axis mod by kevinakasam (https://www.thingiverse.com/thing:4243512). I have two Longer LK5 Pro printers, so I figured I would mod one and see how it turned out. Since the frame is a bit different I had to make a few changes to some of the parts. The parts with LK5 Pro in the name are the modified parts specific to this model. All the other parts are the same as the original mod, I just felt like it made sense to have them all in one place (that, and I'm lazy and just put everything in the folder here).

I included 3 different left and right gantry brackets. The mounting holes are different than the Ender3 so one of these must be used on either side. At this time, I have only used the Left Bowden file.
The regular ones that don't have a bowden type extractor are just left and right.
I mirrored the left side bowden brackets and overlaid the holes from the right side bracket to create those files, so hopefully everything is still properly lined up.
I had bowden models that incorporated the guide from Longer. I finally got to try the the model with the guide, it does not line up properly and seems to put too much resistance on the filament, causing the extruder to squish it and skip. I am removing those files until I can remodel it to line up properly.

I made the bottom brackets go around the side since the frame Longer uses doesn't have the t-slots across the top, and drilling and tapping holes for that didn't seem too prudent. There are two styles, the f263 is for the smooth pulley and the 20T is for 20 tooth cog pulley.

I added an arm to the top brackets to work with the support brace, I didn't have any nuts to use when I put it together, so the picture shows it just in the part. It worked, but I'm still putting a nut on it when I get a few.

I turned the bar across the top 90 degrees and drilled new mounting holes for the uprights so the top brackets and transmission would mount. If you have access to a milling machine, this a pretty easy task with the proper bits. For some reason we had a 10MM end mill at the shop, that worked for the counter-bore. Doing this goes perpendicular through the original holes as well, so you must be careful not to use to large of a drill bit. If I think about it when I mod the other printer I will add pictures of that as well.

This printer is larger than the Ender3 and as such requires a longer rod than what the the kit comes with, as well as another length of belt.

I used PLA+, but as the instructions state, it is not a good idea for the transmission parts, however, I also found that it is not a good idea for the bowden bracket either. It's working for now, but I am hesitant to have it run for really long prints until my buddy gets off his lazy butt and prints them in ASA for me.

The original mod linked in the beginning of this drawn out explanation has everything else you need to know about this mod. I recommend using the hardware kit and parts kit linked on the Github page after going through the configuration program, it has a nice diagram on how to assemble averything.