Mustang IRS

Weld your own Unibody: It's fun!

This is where it gets fun. All you jokers out there whining about how you can't have an IRS in your '65 Mustang for cheap take note: This is real cheap. If you really really really want to do this, go for it. I won't stop you. But it's a lot of hard work and precise technique, so don't sue me when your rear end falls out at 80MPH.

Note: Captions are on top of photo renditions

This is the view I suspect most will commonly see... if they happen to be 6 inches off the ground in a Lotus 7. Saw horses help to keep everything roughed in position.

Cool Rear Suspension

The world's best what?!?!? The difference you can...

I've been trying to get my Hooker Headers box in a web pic for a long time. I figure they all come into the UPS man like that. Anyway, I made a template out of a TV dinner cardboard box. Cut and fit.

Frame ties

Here's what I wanted to use that tubing for. This ties the door sill of the Mustang to the inner frame of the Supra. 1/8 inch plate is used on the bottom. A little overkill, but it's all good.

Frame ties

Sometimes saw horses aren't enough. Well, most of the time. I used a tube to support the lower Supra suspension pivot points, and shimmed them to the proper hight.

Shims 'n things

The trunk rails have to be bent, so I cut a wedge in the tube, and bent it to the angle I templated.

Rear frame extention

Here it is, champed in place. This is the left rear trunk area, looking into the trunk from the back of the car.

Left Rear Trunk

Right rear trunk area. Note it's asymmetrical, to clear for the Supra gas tank. We'll use a Mustang gas tank, so it's just going to look all bendy.

Right Rear Trunk

From the bottom, left rear trunk space. Note gas filler hole for orientation.

Left Rear Trunk

Again from the bottom, right rear trunk.

Right Rear Trunk

Heh! I'm welding again!

Right Rear Trunk Welding

This is interesting. I have a frame rail that I would like to connect to the front frame rail. I'm going to extend the front frame rails all the way back, and connect it beside this vestigal rail. Note again the color difference between the Mustang and the Supra parts.

Vestigal frame rail

Cutting a slot for the frame rail. I can weld to these tabs for more rigidity.

Frame Rail Slots

From under the car at the front of the trunk area, looking forward to the front frame rail.

Frame Rail Slots

The rear fenderwells are somewhat structural on a unibody car. The Supra and the Mustang don't quite meet outer wheelhouse to inner wheelhouse, so I'm encouraging them to fit with these templates and some steel.

Wheelhouse Templates

I'm welding steel to the inner wheelhouse to make a "step" meeting the Mustang's outer wheelhouse. Sheetmetal is thin, so I had to carefully stitch weld it together.

Stitching the Wheelhouse on

A big old weld bead fastening the Supra to the Mustang at the door sill. Note the pie cut floor pan meeting the foriegn floorpan. Coooool!

Supra Rear Welded On

It sticks out a bit in the back. That's where the step comes in. Arrow points to where Supra meets Tubing meets Mustang.

Right Rear Trunk

I should leave with a triumphant pic of the whole thing, but I can't get away from the details. It's all welded in, so now I have to patch up spots that still didn't meet correctly. Notice I pie cut the steel I so carefully welded onto the inner wheelhouse, and pounded it over onto the outer wheelhouse with a body hammer. Some dimensions were a little off, so I made a filler out of sheetmetal bent at a right angle. I pie cut one side, and now it bends to conform to the wheelhouse. Lots of stitch welding next time.

Right Rear Trunk