Here is a write up I found on SSM. Enjoy.

Below is what is needed to do a 2 ½-inch body drop on an 86 through 93 Mazda B Series truck.

First off remove your wheel and tire combination from all 4 corners and take the tension off the suspension by removing the shocks, torsion bars, airbags or whatever you have for a front and rear suspension. Place two 2x4’s the width of your truck, one under the front portion of the cab and the other under the rear portion of the cab (in front and behind the doors) and lay the truck on top of these. This will give you a flat platform with which to set your truck on and assure you that when the cab drops after the cutting, that the rockers will be level with the frame rails and also explains why the suspension had to be taken apart.

Now the truck needs to be stripped down of all interior pieces, including the dashboard.

Next the front clip needs to be removed. Before removing the hood you will need to get a general idea of where the air cleaner will be hitting the underside of your hood once the body drop is complete. You will need to remove some of the inner structure of the hood to allow for this clearance, which is easier done when the body drop is completed. Once this has been determined to some degree it is time to remove the front clip of your Mazda. This involves removing the hood, windshield wipers, cowl, grill, antenna, fenders, bumper, radiator and all the electrical harnesses and emissions components that are attached to the inner fender wells, all of which can be placed on top of the engine for the time being. Before removing the radiator mark where the radiator hose comes across the lower frame cross member as this section you will need to notch to allow for clearance at a later time. Once everything has been removed and marked the entire front clip is ready to be cut off the truck. This involves cutting the inner fender wells and inner sidewalls right at the point where they meet up with the firewall. After the cutting you will need to remove the core support mounting bolts, which are located near both sides of the radiator. This entire front clip needs to be cut off and set aside so that you have access to the front core support/bumper mounts, which will also be explained later.

Once the front clip is cut off and removed from the truck it is time to cut the cab. Start by cutting the floor where it meets right along with the doorsills. While you are in this area you will come across the front and rear cab mounts, which are a bit of a chore to deal with, and you will probably go through a couple Sawz-all blades if you are lucky, but like the rest off this job they need to be dealt with. Cut a straight continuous line from the front of the cab to the back of the cab and go through the cab mounts not around them. The inner firewall is then cut where the floor is seam sealed to the firewall. This seam sealed section will have been seen when you removed the carpet. Be careful when cutting the floor as on the passenger side under the floor resides all your rear brake lines, which are about a ¼ inch below the floor. Use a die grinder in this particular area. The back wall is then cut from the floor and up the back wall about 4 inches or so to the back brace that is attached to the outside and runs along the width of the cab. This brace is 3 inches wide and you will cut along the top and the bottom of this brace. Remove the brace and attaching metal and what you are left with is a 3-inch gap that runs from the driver’s side to the passenger side of the cab. Although this is a 3-inch gap you are only going to do a 2 1/2 –inch body drop as anymore and you will need to cut the hood for the engine to stick through and this is a big “no-no”. If your engine is sticking through the hood when you are done then you know you cut too much. Anyway, after all the cutting of the cab is complete a little pushing, pulling and tugging, with the Help from your buddy, the cab will drop on top of the two 2x4’s you placed under the frame rails, thus making the rocker panels even with the frame rails. Now when you look at the back wall you will see that the 3-inch gap is now closed and about a ½ gap remains. Take the brace that you removed earlier and remove the metal that is behind it then take the brace itself and spot-weld it back in place to cover the cut that runs from one side of the back wall to the other. This will give it a somewhat factory appearance even though it is not really seen but it will cover the cut you made across the back wall. Now take the metal you removed from the brace and weld this to the inside of the cab to cover the cut and to reinforce the back wall. This is a nice piece to use because it is contoured the same way as the wall, obviously. There will also be a 3-inch gap that runs along the doorsills as well but once again we are only doing a 2 ½-inch body drop so measure the proper amount and fill this gap using a filler plate as well. Welding the floor back to the inner firewall takes a little give and take and possibly some additional cutting and fabrication with metal filler plates; take your time to do this area as best you can. After all the welding has been completed use seam sealer along all the welded areas and if you choose to you can spray the floor with a sound deadening material or undercoating.

Now the reason the front clip was cut off and removed is so that you can cut off and re-weld the core support/bumper mounts. These need to be cut off from the frame and moved down 2 ½-inches and “tack welded” back into place. You will be cutting thru a factory weld, which is going to take some time, but this is the point where the mount is attached to the frame. After you have removed the mount from the frame the top of the bumper mount needs to be level with the top of the frame cross member which the radiator sits above. Once the core support/bumper mounts have been “tack welded” back onto the frame you will now need to notch the front frame cross member, which you marked off earlier, below the lower radiator hose to allow clearance for it once the body drop is completed. Now set and clamp the entire front clip back on the cab/frame and test fit your fenders, cowl, hood, grill and bumper to check for panel gap, how well the body lines match up with other panels and to see how the bumper aligns with the rest of the truck. If the bumper is to high or to low remove the body panels and bumper and unclamp and remove the front clip. Now you will need to grind the “tack welds” off from the core support/bumper mounts and then realign them where you feel they need to be. Re-tack the mounts and replace and clamp the front clip and install the bumper and body panels once again. This is a trial and error part but if you take your time and do it right everything will line up properly. Once all of your panel gaps are correct you can then weld the bumper mount to the frame using a more “permanent weld”. Now is a good time to direct your attention to the underside of the hood as in where the air cleaner is hitting it, as mentioned earlier. Take care in cutting the underside of your hood as one slip and you will need to do some additional bodywork if not get a new hood.

The bed is cut pretty much the same way the cab was done in that a 2 ½-inch section is removed from the two sides. The head gate (back wall) of the bed is bolted to the bed and is removed by unbolting it from the bedsides after which a 2 1/2-inch section is cut off the bottom of this panel. There's a support cross member/rib under the floor of the bed at the tailgate end, which you will need to cut right next to. It is nearly impossible to cut through it so cut around it as much as possible. Once the sides have been cut and re-welded together the head gate is bolted back on the bedsides and the bottom of the panel is then tack welded or screwed to the floor of the bed. Fill the gap that is at the tailgate end of the bed much the same way you did the cab and you are ready to put your truck back together. You may need to put shims on top of the bed mounts which are on the frame as the chances of getting the bed lines to match up with the cab lines are pretty slim, no one is perfect.

we need some pics on this if at all possible bro

other than no pics i feel i understand the body drop process much more. i can picture it in my head now. it doesnt seem as hard as i was thinking, even though im sure it is a bitch to do

yeh it sounds extrememly easy on paper. but as we all know when it comes to fabricating it isnt the big things that stops you its all those little things that you dont think about and comes right up to bite you in the butt

Good write-up

maybe one day ill get to use this write up

it's not for the meek....
but with some thought and patience anyone should be able to do it.

I am sure we could pull it off devon. Its not like fabricating is new to us or anything.

do you suggest bagging the truck first or does it matter i would like to do a 2.5 body drop bagged with 22's on my b2200 ppl tell me it wont be possible but i dont know what is your suggestions