Seems like most crossover toolboxes are similar in size, but there's many different designs. Some are deeper, some are taller above the rails, etc. Hard for anyone to tell you what size to get, when we dont know what all you're trying to put in it. I have a couple, one is a tracbox that slides front to back of the box on the rails for my ladder rack, very slick, but it could always be bigger. I also have a gullwing box that I had on my chevy, that box was really nice for storing small tools, as it was much easier to access from the side of the truck, whereas the other one pretty much requires you to jump up in the truck bed to get anything out of it. Lastly, I had some side-mount boxes on an older truck. Great for small tools and such, but not big enough for anything larger, but nice because I still had 4' between them in the truck bed for gear. All comes down to what you need and what you like I guess, just dont go cheap, there's alot of cheap garbage out there that wont hold up over time.
Silly--the gull wing style generally is a cross-bed design. I've got an in-bed box made by DeeZee that is 2 feet wide. Because I have an 8 foot bed, this gives me 6 feet of useable bed. I have plenty of room for my shotgun shells, lacrosse stuff and auto stuff. It came with a sliding drawer, too. But, if I was going to us it for tools and stuff, this would be too small. So, ask yourself what you want to carry in the box and in the bed at the same time. By the way, I wanted an in-bed box because I wanted the room on the rails for an overhead rack.
I have a crossover box in mine. The one thing I did not consider is the height of the one I bought blocks my view of the rear of the bed so judging the back of the truck for backing up is much tougher. You may want to consider this.
Try to find one that is low profile even if it sits in the bed deeper. I don't have a real tall box but wish I had gotten one even lower. And get one as narrow as you can and still have room to mount. Some stick out past the edge of the cab as it starts to tapper in and makes the box look goofy.
I bought a used tool box from a guy at work. Not an exact fit, it's slightly narrower than the bed box but still has enough on an overhang on the rails to be secure. I drilled two holes on each side for 1/4-20 stainless hardware to bolt it down. Then I got an Extang "tool box tonneau cover" which fits between the tool box and tailgate. They fit and work well as a pair but I took them out when I needed the full bed. I will be putting them back in soon, just have to finish up a few tasks with the bed empty.
One thing I also got was a Load Handler truck unloader. It straps to the tailgate and you crank in the drag sheet to pull the load off the bed. I did several 1 yard loads of rain soaked screened loam(the guy at the yard said it was running close to 3000# per yard), it handled them no problem even without a low friction mat in the bed. While the Load Handler will fit in the tool box, I would have to take out the small parts tray that slides back and forth in order to get it to fit. I think I will just put it in the bed under the tool box, along with the broom and shovel.
All in all I'm happy with the entire setup, but I'll probably end up getting LineX at some point down the road. Then I'll need to get one of those low friction mats in order to get the Laod Handler to slide properly...
I'm headed out of town tomorrow for a week, I'll try to get pics of everything in the bed after I get back.
from work experience bigger is better, get the deepest one the low profile in my opinion looks worse but it also doesnt have the side pockets under the lid over the bed rails standard.
i have a husky diamondplate i have had one before that one is now on one of our other company trucks its a good box, rest of our work trucks have the weathergauard diamond plate box, deep and wide enough (front to back) to put most power tools in and tool bags in and is the most secure and durable box there is...size security durability next one i have will be weatherguard
A couple more ideas:
1. Put a 4 x 8 sheet of good plywood, finished one side in the bed first. It will save your knees, if you need to climb in bed (with 8' bed)
2. Buy a tool box that stays off the rails. ESPECIALLY if you plan on a cap.
3. Mount the tool box using 2-2x4's (lifting the box 3" off plywood). Then if you need to haul something 8' or 10' long (on tailgate) you can easily do it.
4. I have a 2' wide tool box. Inside I also compartmentalize with good plastic boxes. I carry my chains & binders, tools, jack, spare parts, trailer locks, and now dirt bike accessories.