Author: DW

Mustang II Crossmember Trim Lines Worksheet

Welder Series has a free service to help builders lay out the crossmember and upper tower cut lines. If you fill them out, take pictures of them, and email the pages back to us, we will give you drawings showing the sections to be removed. These worksheets can also give us the info we need to provide you with boxing plates. We’d give you a price for the plates and you can decide if you want to order them or make your own.

MII frame dimension tech sheet

Mustang II crossmember excess material

Dear Welder Series… trimming excess off crossmember

Dear Welder Series…
Hi DW I’m pleased to say I have the main section of my mustang 2 kit installed in my frame rails, the instructions were clear as a bell and it is a beautiful piece of work. I was just curious if it is recommended to remove any excess metal on the outer edges of the crossmember or not to give it a cleaner look. I’ve attached a picture to show you what I plan to remove. Thanks again and hope to hear back soon.


Mustang II crossmember excess material

Dear Anthony…
You can trim the area indicated. But it feels like there’s another problem coming regarding the towers. It looks like the frame is too narrow to attach them. Have you got past this issue or should we talk? Please call 888-648-2150 if you want to discuss it. Leave a message and I get back to you.
Paul Horton

Dear Welder Series…
Oh thanks Paul. I did end up getting everything mounted onto the frame and all the measurements checked out so here’s an attached picture with the lower crossmembers and the upper control arms mounts all tacked in place. If this doesn’t look right let me know.

Dear Anthony…
Anthony, it’s hard for me to get a perspective on the tower and crossmember but maybe this sketch will help.
The front upper-inner corner of the tower should be very close to 9-3/4” higher than the lower pivot hole center. The rear should be very close to 9-1/4”.
The vertical edge of the tower should be 1-7/8” inches out from the lower arm hole.
I hope that helps.



I wanted to give a little shout-out, as they say, for the kit that controls my overdrive and torque converter lockup. Here’s the link:

I was whining to a customer a couple years ago about how high my D100 was revving on the highway. I could barely get to 55 mph and it sounded like an indy car. Maybe I’m exaggerating.

He told me I could add an overdrive transmission to the back of my 318 with “very little work”. Those three words often accompany a lot of work, so I was skeptical. A local transmission shop (Tri City Transmissions in Kitchener) sourced the A518 out of a pre-1995 Dodge pickup, and I got to work installing it. This was happening right before my annual trip to Syracuse, and I found out by doing the swap on my own that transmissions are heavy. You’ll need to move the transmission mount somewhat, but we have some parts for that. Check out the link for a kit that will let you control the overdrive and lockup without a computer. It’s been working flawlessly for a couple years now. Make sure you have consistent vacuum (I had an arcing spark plug wire and it caused a lot of frustration during my first trip).

Let me know if you have any questions about the swap! I’ll see what I can do to remember an answer.

Dear Welder Series… Triangulated 4 bar with Buggy Spring?

Dear Welder Series…
I am currently building a model a coupe and working on the rear suspension. I have a couple of questions. I’m going to use a buggy spring and was planning on using a 40 Ford wish bone but I’m having my doubts as to weather it will hold up under the power of a nailhead. My questions are can I run a triangulated 4 bar with the buggy spring? I’m also leaning towards ladder bars. Can these be modified and scrap the clevis fittings on the rear mount in favor of urethane on all the joints or would it make it too stiff of a ride.
Thanks for any help,

Dear Kevin…
Sounds like a neat project, Kevin. The triangulated rear 4-link can be used with the buggy spring if the spring is mounted behind the housing. If the spring is on top, it might interfere with the upper bar brackets.

If you decide to use the ladder bars, it will be much easier to stay with the clevises. The front-mounted urethane bushings isolate the whole assembly, so the ride will be pretty much equal.

Thanks for looking at Welder Series parts.

32 Update: Front Leaf Spring

“These cars are way oversprung.” There, I’ve said it. I don’t think I’m the only one, but now that I’ve changed the front spring, I’m even more confident.

Originally, the car was built with a mono leaf spring over an aluminum I beam axle. The mono leaf has only one leaf (“mono”, not the kissing disease), and it’s kind of like a graduated spring rate… it’s thicker at the middle and thins out towards the eyes. It’s probably quite softer than a seven leaf spring, but it’s definitely not softer than the Posies super low spring I installed two years ago (2016).

Combined with a new set of Ridetech aluminum front shocks designed specifically for light, solid axle cars, the ride is much, much better. The shocks are a dramatic (I don’t often use italics) improvement over the standard chrome shocks I had installed originally… they’re designed with almost no compression damping because – you guessed it – these cars are way oversprung already. Almost all the damping is in the rebound, where the shock needs to control the heavy spring throwing the light front end back up after a bump in the road.

I think I began to question front leaf spring rates when I was trying to find a squeak in the front end. You may have done the same thing – stand on the frame horns, bounce the car, try to reproduce the noise. While I was doing that, I noticed that most of the “bounce” was in the sidewall of the tires, not in the actual spring. I’m sure the sidewalls serve an important role in absorbing road imperfections, but they’re certainly not up to the task of handling much more. Ask your kidneys after a ride in a 90’s era mini truck.


Dear Welder Series… Mustang II crossmember notching

Dear Welder Series…
Does the coilover crossmember for a Mustang II go up the outside of the frame or do you have to notch it in?

Dear Don…
Hi, Don.

The crossmember and the upper spring towers get notched to fit the frame dimensions. Usually, the crossmember welds to the inside and under the frame rail but this depends on the track width, frame inside and outside dimensions, and the frame height relative to spindle height.
I can show you where the frame and tower notches will be for your application according to the instructions at: .
Please send the following dimensions:
Spindle height or front tire size you will use
Frame width, inside
at CF
at CR
Frame width outside
at CF
at CR
at TF
at TR
Bottom of frame to ground
at CF
at CR
Top of frame to ground
at CF
at CR
at TF
at TR
With this info, I’ll be able to show you which kit width will fit and how the crossmember and towers will have to be notched. I can also make suggestions regarding stock or dropped spindles. Then you can position your wheels and tires and see how the truck will look.
Thanks for getting back to me. I want to help you with your project.

Dear Welder Series… Corvette sway bar questions

Dear Welder Series…

I am wanting to install a rear sway bar on my 1978 corvette. Due to modifications to corvette and rim/tire size, a factory bar will not work.
This kit seems to be the closest to what will work for me but it I am hoping to get some more information from you before I purchase.
1)  Can you confirm the length of the torsion bar is 45″? If not what is the actual total length. The corvette frame is right around 43-44″ wide  and it needs to sit directly under it. There is minimal area to go narrower but is probably possible. Obviously I can trim it too.
2)  The outer tube what is the supplied length?  — so I can figure out if an under frame mount will work or I will have to fab up some custom brackets.
3)  What does the under frame mount look like?
4)  The lower link mounts won’t work in my situation so can they be removed with the  coil over mounts for a bit more cost savings.
5)  Do you have a detailed drawing (or a scale PDF) that I could print out, cut out to see if it would work around the interferences I have.
If you had a 45″ kit without any bracketry (swaybar , tube, bushings, arms, couplers and rod ends for the links)  that would be ideal.

Dear Mike…
Hi, Mike.

1)  The actual sway bar is 45” long. One end has 1” of spline. This bar is designed to be used as-is or cut to length. We also have 45” bars splined both ends. The 3/8” thick arms mount outside the bar, so if the 45” bar was used as is, the distance outside the arms would be 45-3/4”.
2)  The supplied outer tube is 1-3/8” OD and 43” long.
3)  The under frame mounting bracket:
4)  The lower axle mounts for the links can be taken out of the kit:
5)  I don’t have a single drawing of the whole kit. Dimensions for the various parts should all be on the website.
Welder Series is a “builder supply” company and, as such, all parts are available individually. They are shown on our website with dimension details. Please get in touch again if we can give you some other info.
Thanks for looking at our parts for your project.
Paul Horton
Dear Welder Series…

Thanks for the info, it helps greatly.
I am just working out  how to best mount it, what parts will work in my case and also ways to keep the weight of the added system in check.

Dear Welder Series… Unhole Tip

Dear Welder Series…
I tried to attach these to the review but it wouldn’t let me. I found that if I used a step drill and drilled the finish dia of the plug (5/8″) 1/2 way thru it left enough shelf to support the plug and was tight enough to fuse with the TIG.
I hope this helps,

Dear Jim…
Great idea! I hope someone else sees this and is able to make use of it. I always find it a bit of a hitch in my step when the next size on the step drill isn’t quite far enough away to go through the whole thickness of the material, and it leaves a lip that needs to be removed… this idea almost redeems that :).

Dear Welder Series… MII for Datsun 521?

Dear Welder Series…
Hello, I was looking at your Mustang II crossmember kit. I’d like to get one for my Datsun 521. I was wondering if you would be able to decrease the width of the crossmember sections by 3” to accommodate the more narrow track width of my truck. I guess I could section it myself but that wouldn’t look as clean. The suspension parts aren’t readily available for my truck so I’d like to use this setup.

Dear John…
Hi, John.

We can make special width crossmembers, but…
The actual track width might not turn out to be what you hoped for. The brake kit used can move the wheel in or out from where the stock Mustang II was. You might also find that narrow control arms can be used that will reduce the track width and give more clearance in the engine room for exhaust and steering, even if you will use the stock engine.
Our website has some Mustang II dimensions at These dims will give a track width of 56-1/2” when stock 1974-78 Mustang II rotors and control arms are used. Narrowing the dimensions, top and bottom, will bring the wheels closer together by that amount. Shorter control arms will do the same. The brakes used might move the wheels in or out. We have info about our brake kits at:
If you use 4-bolt MII rotors, there should be no change.
My suggestion is:
Get everything you need except the crossmember kit, springs, shocks, and the steering rack. (Wheels & tires, brakes, spindles, and control arms)  A custom rack will have to be ordered after the width has been determined. Springs and shocks can come after that.
Remove the stock front suspension.
Block the truck at ride height.
Mock up the wheels & tires, rotors, spindles and lower control arms.
Position the tires in the fender. The tires should be very close the vertical.
Block the lower control arms at horizontal.
Measure the lower control arm mounting hole center-to-center.
Subtract that dimension from 22-1/4”. This is the amount to remove from the crossmember.
Buy our 56-1/2” kit and remove that amount from between the rack mounts.
The rack will have to be shortened the same amount.
Before doing much more, check the cost of this to be sure you are comfortable with it.
I hope this helps with this part of the project.
Paul Horton
Dear Welder Series…

Thank you for all the information and help. I figured that the control arms would have to be shortened as well. I saw a couple of your customers vehicles who did the same thing. Have a Happy New Year.