Mach Rear Frame Rail Replacement

[69basketcase 10]

Good morning folks,

 

Proud new owner of quite possibly the most rotten 69 Mach 1 in the south. I bought this car as a project to do with my father (who has leukemia), as the 69 has always been one of his favorite cars. I have always been a Jeep guy and have built a couple rock crawlers as well as restored a few classic CJ's, but this will be a first for me.

 

Fortunately, the previous owner spent years collecting most of the parts. I have all new Dynacorn sheetmetal for 90% of the car as well as a lot of the hard to find original parts. Only pieces I am lacking are motor/trans, console, and rim blow steering wheel.

 

The car was originally a Dark Jade Metallic, M-code 351W, 4-spd but the original motor and trans are long gone. I realize the purists are going to flame me, but the goal for this project is to do a 428CJ, 4 spd, clone in Acapulco Blue (as that is what the old man wants). The car will not be numbers matching regardless, so I don't see installing a 428 as blasphemy as long as I do it right.

 

I have the car stripped, catalogued, and the front half has been sandblasted. My questions are as follows:

 

1. I am replacing the front battery apron, rear driverside apron, and radiator support. According to my measurements (from the inner fender/cowl bracket to the radiator support), the front end is roughly 1/8" to 1/4" out of square. What do my measurements need to be? I was going to use the 3 bolt holes on the shock tower to line up the battery apron and square the radiator support to the original side before I removed the rear driver side apron. Does this seem reasonable?

 

2. I have a one piece trunk trunk pan and shock crossmember to install. The passenger side rear frame rail and torque box seem to be in decent shape (just surface rust from what I can see). The driverside rear torque box seems ok, but the frame rail is tweaked from a long ago accident. My plan was to drop the entire trunk, frame rails, and torque boxes as one assembly and use them to take measurements to fab up the new trunk floor with new rails and boxes and then install the whole thing as one assembly. The new rear quarters and tail panel would then be fit to this after it has been properly fit to the original panels. The rear of the body would be braced and supported accordingly. How is the fitment of the dynacorn boxes and frame rails? Is this plan reasonable or is there a better way?

 

I apologize for the above novel. I just wanted to ask the experts. I am not a novice by any means when it comes to fabrication, I just have never worked on a unibody Mustang before. I certainly appreciate any feedback. Thanks!!!

[MustangChuck 16]

Welcome to the forum!

 

First, you will find this forum is very open to modified Mustangs. No flaming (though some light ribbing) happens here. I think you'd get more unhappy responses if you had said you were installing a GM power plant. Lots of folks here step up to big blocks.

 

I personally love the Dark Jade Metallic. The Blue is also a nice color.

 

It is my understanding that the Dynacorn pieces are probably the best on the market, so getting them to fit correctly should take much less effort than cheaper generic Chinese pieces.

 

I have attached the frame measurements for the 69/70 Mustang. Hopefully it will help you with your work.

 

Chuck

[manley 13]

I realize the purists are going to flame me, but the goal for this project is to do a 428CJ, 4 spd, clone in Acapulco Blue (as that is what the old man wants). The car will not be numbers matching regardless, so I don't see installing a 428 as blasphemy as long as I do it right.

 

When it comes to cars in that kind of condition(like mine), it's almost stupid to try to make a concours correct restoration unless it is something super rare, in my opinion of course.

 

I have the car stripped, catalogued, and the front half has been sandblasted. My questions are as follows:

 

1. I am replacing the front battery apron, rear driverside apron, and radiator support. According to my measurements (from the inner fender/cowl bracket to the radiator support), the front end is roughly 1/8" to 1/4" out of square. What do my measurements need to be? I was going to use the 3 bolt holes on the shock tower to line up the battery apron and square the radiator support to the original side before I removed the rear driver side apron. Does this seem reasonable?

 

That's pretty good actually. When I was replacing everything up front (except the framerails), I measured an inch difference from left to right when I looked at 3 different cars. The tolerances on these cars were not tight at all.

 

...

[69basketcase 10]

Certainly appreciate it! Attached a few pics of the project so far.

[69SlowResto 19]

Welcome to the forum! I think your plan sounds great for that car. Dark Jade is my 2nd favorite color but Acapulco Blue is my favorite, that's what I will be painting mine. I think that's great that your building it with your dad, it should be a great experience for you guys. Keep posting pictures and updates.

 

Cheers

 

Lee

[latoracing 256]

Welcome to the forum. Sounds like you have a fun project to play with, espically with you father, that is just cool in itself. Love the blue also, and the FE power / 4-speed. The aprons and rad. support are no problem to do. The complete frame rail / trunk floor will be interesting. I have put a bunch of Dynacorn sheet metal in my '70, and have been pleased with most of it. I'm shure frame rails will be quality as well.

 

Sitting here thinking about how much stuff connects to the rear of the car and building it outside of the chassis is quite possible with the shock mount and rear cross member, it should stay "square", but I don't know if I'd fully weld all of it before I got it reconnected to the inner wheel house and outter rockers, just in case it needed a little tweek.

 

Unibodies are not that bad to build, all sheet metal, and the whole assy. makes it strong. Having a good foundation makes these cars a pleasure to drive, unless you like flexible flyers. Post lots of pics, and good luck with your build.

[69basketcase 10]

Just thought I would provide an update to our project.

 

Using the drawing provided by MustangChuck, we fabricated a jig for the car to sit on. It uses machined pins to locate the front frame rails/torque boxes and the rear frame rails/torque boxes. The car was then clamped to the jig at the pinch welds. The rear section of the jig is removable and locates using pins. We did this so the rear frame rails and trunk floor could be installed.

 

Why in the world Dynacorn makes frame rails and torque boxes for the 69 fastback, but does not sell them individually to the public is beyond me... We were forced to use Mr. Mustang frame rails and torque boxes and their quality is lacking (to put it politely).

 

All that said, the entire car has been disassembled, sandblasted, and sprayed in epoxy primer. We have replaced the battery apron, radiator support, rear driver side apron, driver side outer cowl panel, toe boards, one piece floor pan, one piece trunk pan, doors, quarter panels, trunk corners, outer wheel houses, and deck lid. I guess it would be easier to say that we have reused the roof, firewall, and B pillars (even though they probably should be replaced...).

[69basketcase 10]

more pics

[RPM 1,190]

Wow, what a project, and progress! What a wonderful thing to do for and with your father. I hope for the best for you both. I pity the fool who rags on you for putting in a factory available and highly desired 428. Very nice work so far, especially the jig/ fixture fab. Good luck, and welcome (6 months late) to the forum.

 

Bob

[prayers1 153]

What a GREAT thing to do with your Dad. I wish I had that opportunity. Take plenty of pictures. Put what ever you like in your car, it's yours and your the one driving it.

Mine came as a Base Fastback with a 351, 3 speed. Right now it has a 289, 4 speed, deluxe interior and Boss stripes. So go a head and plant that 428!

 

Looking forward to more pictures of your build, Keep up the great work!

[hoss69 10]

Hi Guys, have just joined up and hope you can help with my resto. My car is a red on red 69 Mach1 with original drivetrain. Has a tach dash,tilt steering column and fold down seat. Now the bad bit! It has rust everywhere. The only part worth saving will be the roof. Would like some ideas on where and what to replace first. I.e inner and outer sills,rear frame rails, A and B pillars.... Will be making a jig as passenger side rear spring hanger has come up through the trunk floor so will need measurements. I saw the frame chart that Mustang chuck put on here,but there seems to be a discrepancy at "A" being 12 3/4 and the rear off rear frame at 11 3/16. Any help would be much appreciated.

[TonyV8 10]

Hi,

 

 

Welcome to the forum from a fellow UK Mustang owner.

 

Phil King in the UK is a good guy to contact if you haven't already. Phil has rebuilt some complete basket cases.

 

http://www.fordmustangrestoration.com/

 

I do not know if you have priced up panels yet but by the time you have paid the shipping costs and import taxes they are going to really add up. Might be worth checking out the cost of these vs a Dynacorn shell if the roof really is one of the few salvageable parts.

 

There are a few people in the UK who can source you a shell I believe.

 

Tony

Edited January 1, 2014 by TonyV8

[jmlay 80]

The measurements in the chart are correct, front rail is higher than the rear.

 

I'm in the process of building a JIG so that I may replace the front frame rails, no rust prior accident damage with poor repair. Sorry for the poor photo's, it was cold & dark.:

 

 

 

 

[RPM 1,190]

The measurements in the chart are correct, front rail is higher than the rear.

 

I'm in the process of building a JIG so that I may replace the front frame rails, no rust prior accident damage with poor repair. Sorry for the poor photo's, it was cold & dark.:

 

 

 

 

 

 

Smart move, I like the way you think!

 

Bob

[hoss69 10]

Hi Tony, The dynacorn option would great but I don't have £16,000 to buy one. Even if I had the money I still wouldn't buy one as I get a lot of satisfaction out off doing all the work myself. Have had two 70 Mach1's in the past and both needed new floors and stuff, but not as bad as this one. Silk purse out of a cows ear comes to mind. I already have some parts coming over in a container from sts imports that should be here in a week or so. Will also be going to Toronto, Canada in the summer to see some friends,so will be doing some shopping at Golden leaf automotive and any swap meets I can find......Thanks for you're reply, and wish you a happy new year.....Mike.

[hoss69 10]

Hi Mike, thanks for you're reply. Your jig looks great. What size is the box section you are using? And will you be raising the jig off the ground so you can get under the car?

 

Happy new year.....Mike.

Edited January 1, 2014 by hoss69
spell check.

[TonyV8 10]

Hi Tony, The dynacorn option would great but I don't have £16,000 to buy one. Even if I had the money I still wouldn't buy one as I get a lot of satisfaction out off doing all the work myself. Have had two 70 Mach1's in the past and both needed new floors and stuff, but not as bad as this one. Silk purse out of a cows ear comes to mind. I already have some parts coming over in a container from sts imports that should be here in a week or so. Will also be going to Toronto, Canada in the summer to see some friends,so will be doing some shopping at Golden leaf automotive and any swap meets I can find......Thanks for you're reply, and wish you a happy new year.....Mike.

 

 

Hi Mike,

 

That's great sound like you are well clued up and have a plan in place so scrub the Dynacorn option!

 

My Mustang requuired new bonnet ,wings, front panel, boot, rear panel, rear boot floor rear inner wheel arches one rear panel and passenger floor and a lot of metal work around the front cowl.

 

I hope the build goes well and a Happy New Year to you as well.

[jmlay 80]

The body will not set on that plane. I have crossbars that will have vertical extensions to raise the car above the 14' rails. The intent is to be able to stabilize the body & allow me to use the rails for the datum line to ensure all is true per the chassis drawing. The legs are 8"s & the frame rails will be 6-8 inches above the "able" rails, total of 16-18"s off the ground.

[69basketcase 10]

Hi Tony, The dynacorn option would great but I don't have £16,000 to buy one. Even if I had the money I still wouldn't buy one as I get a lot of satisfaction out off doing all the work myself. Have had two 70 Mach1's in the past and both needed new floors and stuff, but not as bad as this one. Silk purse out of a cows ear comes to mind. I already have some parts coming over in a container from sts imports that should be here in a week or so. Will also be going to Toronto, Canada in the summer to see some friends,so will be doing some shopping at Golden leaf automotive and any swap meets I can find......Thanks for you're reply, and wish you a happy new year.....Mike.

 

I'm fairly new to this so definitely listen to folks with more experience but I can tell you that using Dynacorn parts are well worth the extra $ (maybe not buying a whole shell...). We have literally replaced every piece of sheetmetal on this car except for the roof and firewall. Dynacorn parts required very little mods, if any, to fit. "other" name brand pieces did not fit at all.

[69basketcase 10]

Our project has taken a bit of a turn from the original idea and we are now going to build a "pro-touringISH" car. Motor has been purchased and will be revealed later in the build :001_cool:.

 

Does anybody have any experience with TCI's IFS kit or their 3 link rear? I've read mixed reviews on different forums. I worry about the fitment of the rear because I am really not happy with the quality of our rear frame rails.