Full Tub

The following document is not really a How To but more a guide to performing a full tub to an 85 Mustang GT. Because there are so many variables that can be encountered while doing a full tub it would be impossible to write up a How To on the subject.  Below I have outlined how I ended up doing a semi full tub to my Mustang plus alternatives to doing full tubs to Mustangs.

Do you think you are ready to tackle this type of job? Well take a glance at some points I have listed below.

You will run into several issues when trying to do a full tub to the Mustang. Besides knowing how to weld and having a good working mechanical mind the following issue may arise:

Still dreaming of a full tub job? Read on!

So you are still interested in performing this modification..... Below I have listed some points and possible ways to arrive at your goal. In the information below it may seem as I am endorsing S&W for performing this type of mod. This is not so. Although I have had nothing but good experiences from just about every product I purchased from them I stress that you should choose your parts by researching them. Don't take any one word on any product. Get the facts and find out who is happy and who is not.


Tub Kits:

A tub kit is absolutely the easiest way to do a full tub to a Mustang. There are several companies that make narrowed weld in rear frames for the Ford Mustang. Because of all the welding required it would have taken half the time to do the tub job than it did if I would have used a kit. The rear frame will come almost completely welded together. You will mainly have to remove any frame material specified by the manufacturer of the kit and weld in the new frame. The rear frame kits usually come with your choice of ladder bar or 4 link control arms and your choice of coil overs and spring weights. Very simple and comes in one package.

Ladder bar Kits:

There are several manufactures of ladder bar kits. Of all the kits I have seen almost all are basically the same design. My suggestion is to ensure you get the adjustable ladders bar kit. This will allow for greater adjustments in the suspension to really dial in your combo. I used S&W ladder bars for my car and found them to be of excellent quality.

Coil Over Kits:

Again there are several companies out there that sell coil over kits. There are so many type and brands I can't even begin to list them. I choose the S&W coil overs as well for my project. I was not completely happy with the appearance of the coil over shocks I received from S&W but will wait for track results to make a final decision on there quality and durability. The coil over kit itself was of good quality and the install a breeze but the shocks itself seemed a little cheap to me.

Frame Tubing:

Frame tubing can be purchased from several sources such as S&W. In fact you could probably find what you need at a good steel mill or steel shop. The frame tubing can be either round tubes or boxed frame rails. I used tubes for my frame since I only cut out a 2 1/2 foot by 3 1/2 foot section of my frame. If you are going to be hacking out a larger space you may want to move to a boxed frame rail. In either case you may be required to make bends and angles to certain areas of the frame. Some racing shops that sell frame supplies will have pre bent tubing or pre bent boxed frame rails. Purchasing pre bent frame rail may be the way to go for a cleaner and more professional install.

Rear End:

Rear ends are dime a dozen. If you have an 8.8 now the cheaper route would be to beef up your existing rear but if you still have the stock 7.5 rear I would suggest the 9inch for the build up. Although both the 8.8 and 9 inch are tough rear ends, can handle lots of abuse and very popular the 9 inch aftermarket world is endless where the 8.8 eventually drops off. The 9 inch rear overs unlimited rear axles ratios and the removable center section allows for quick a and easy gear changes. I choose to stick with the 8.8 for my project since I acquired one so cheap.($300 bones with 3:73 gears already installed)

How I performed my Semi Full Tub

You will notice in the picture above that the rear frame rails are not straight with the body but rather angle out where the old stock shock mounts. The frame is straight in line with the body before the shock mounts. Narrowing this frame rail piece will give you almost 5 more inches of tire space with out back halving the entire car.

Here are pictures of the rear frame tubes I installed. The picture to the left was taken before the crass bar for the coil overs was welded in. What you can't see from this picture is that there are four bars running between the two stock frame areas. In the picture to the right you can see that one bar on each side is visible. Under the square box frame rail looking pieces are another set of bars running between the frame areas. Although this is probably not needed I added them in for extra support.

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In this above picture you can see the top braces for the narrowed rear. I placed two braces from the top of the main hoop to the top of the stock upper control arm area to add extra support to the portion I removed. I then ran two more tubes from the main rear tubes to the area above the coil over brace. This added support to the coil over area and really strengthened the entire rear area. I have two main bars running from the top of the main hoop to the rear frame of the car to give the entire rear full support.

Here are pictures of the ladder bar mounting brace that connects to my main hoop of the Sportsman roll cage. Although you can't tell from the picture on the left the picture on the right shows what part of the rear passenger floor area I had to remove.

Here is a finished shot of the new rear passenger foot area. You can barley tell but if you look close you will see that I added a small 8inch tub close to the edge of the boxed area of the rear passenger floor area. These tie the ladder bar main mounting bar that runs between my main hoop to the front of the stock rear frame rail. It's hard to explain but I think this will help strengthen up the rear frame area a little more and mainly provide me piece of mind.

Here you can see what is cut out and how much. Note that you must leave a 1 to 2 inches of the stock wheel well to weld the new tub to.

Here is a underside look at the new wheel tubs I installed. Mark did an excellent job on the wheel tubs. This was the only part of the rear tub job I did not perform myself.