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71/72 Bumper on a 73. (How Im making it work)
#1
So i know people say it won't fit but i had one laying around and love the look of it. 

So its not finished but i figured i would share how things are going.

FIRST AND FOREMOST: If you are worried about the the 73's safety/crash rating this may not be for you. I am not an engineer and do not gurantee any structural integrity. However this should be better then a fiberglass bumper.

Needs: Angle Grinder with cut off wheels, Drill Press or Drill, stepper bit, Grade 8 bolts, washers, nuts,  grinding bit to widen bracket holes(maybe)


1)  I cut the bumper brackets off. You have to notch the structure from the edge  to about an inch away from the hole seen below: You need to cut along where the urethane meets the metal. Get as close as possible

[Image: 37618148_10160562782025521_4429463269161304064_n.jpg]

2) You will need a good piece of angle iron. About 36" long. It goes from the inner hole on each bracket. You will need to make at least 4 holes. 1 set for the frame brackets and one set for the bumper.  I made 6, as there are 4 holes on the bumper bracket as is. I made these holes oversized for as much adjustment as possible.  The angle iron will sit on top of the bumper bracket .

You also may considering drlling several small holes from one side to the other. The purpose of this would be once everything is fit properly you can use self tapping screws to keep the angle in the right place for welding in place without worrying about it shifting.
[Image: 37626320_10160562782335521_8226996914751537152_n.jpg]

3) You have options here. I believe there is room to drill a new hole above the top slot but it will be tight. I didnt think about this and just started wallowing out the hole for adjustments. I am going to make a plate on the back of it when its all done and weld in place. As you see below i have started this process but the bumper currently sits a little too far to the drivers side and needs to come up about a 1/4" The angle iron should sit close to even with the top edge 
Also you will want to not atleast the bottom outside edge of each bracket otherwise the bottom of the urethane bumper will hit it

[Image: 37620952_10160562782165521_7900695622070566912_n.jpg]

I hope to get as final fitment next weekend but i just wanted to share the results so far. 

[Image: 37603458_10160562782405521_7065758467968991232_n.jpg]

aluminium oxide molar mass

73 Coupe 302/c4 Project
65 Fastback Conversion Eleanor Project

[Image: sigpic53231_7.jpg]

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#2
You could just use 71-2 bumper brackets.


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#3
(07-22-2018, 07:23 PM)Hemikiller Wrote: You could just use 71-2 bumper brackets.

That would require changing out the fenders and grille. The early bumpers sit a few iches higher. In retrospec i could of used then and cut a few inches out to lower it. Welded it back  together and reinforced it

73 Coupe 302/c4 Project
65 Fastback Conversion Eleanor Project

[Image: sigpic53231_7.jpg]

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#4
@JRANGER
You should! I did this swap like few others.

The last in date who did this is @robsweden, he posted last week
https://www.7173mustangs.com/thread-whit...turnsignal

Aside personal choices to close or not the gap between lights on the valance (I did, Rob is about to),
For the sake of aesthetics, additionally you might want to make some plate to close the small gap between the grille and bumper.

73 modified Grandé 351C. Almost done. 
71 429CJ. In progress
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#5
(07-23-2018, 04:57 AM)Fabrice Wrote: @JRANGER
You should! I did this swap like few others.

The last in date who did this is @robsweden, he posted last week
https://www.7173mustangs.com/thread-whit...turnsignal

Aside personal choices to close or not the gap between lights on the valance (I did, Rob is about to),
For the sake of aesthetics, additionally you might want to make some plate to close the small gap between the grille and bumper.

that was the plan!!! What did you use for that piece?

73 Coupe 302/c4 Project
65 Fastback Conversion Eleanor Project

[Image: sigpic53231_7.jpg]

[+] 1 user Likes JRANGER's post
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#6
[Image: 73chrome2.jpg]

To fill the space between lights, make a moulds and got myself a carbon fiber part out of it. Totally useless and polyester or an aluminum plate would do just fine. Its just I was having some laying around and no polyester Smile To secure it, I have 2 bolts on each side, set on the light bracket.

[Image: space.jpg]
This is the missing plate on 73 grilles that needs be done (if you want to)

73 modified Grandé 351C. Almost done. 
71 429CJ. In progress
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#7
Ill have to look into that. I still have my 73 bumper so ill have to see if it has anything i can pull off of it :Smile That or i can see if ABS will work. I will grab some carboard after i finish the bracket and start test fitting stuff

73 Coupe 302/c4 Project
65 Fastback Conversion Eleanor Project

[Image: sigpic53231_7.jpg]

  Reply
#8
(07-23-2018, 07:34 AM)Fabrice Wrote: [Image: 73chrome2.jpg]

To fill the space between lights, make a moulds and got myself a carbon fiber part out of it. Totally useless and polyester or an aluminum plate would do just fine. Its just I was having some laying around and no polyester Smile To secure it, I have 2 bolts on each side, set on the light bracket.

[Image: space.jpg]
This is the missing plate on 73 grilles that needs be done (if you want to)

The more i think about this, the more it gives me an idea....I have the original 73, so i can just put masking tape all over it and do a few layers of fiberglass on top. This should give me a good "Template" to base the piece off of.

73 Coupe 302/c4 Project
65 Fastback Conversion Eleanor Project

[Image: sigpic53231_7.jpg]

  Reply
#9
(07-24-2018, 07:35 AM)JRANGER Wrote: The more i think about this, the more it gives me an idea....I have the original 73, so i can just put masking tape all over it and do a few layers of fiberglass on top. This should give me a good "Template" to base the piece off of.

Assuming here that you want the shape to be as nice/smooth/straight as the bumper and not have to sand for ages because of the polyester thickness diffs.
That's what I call a "good bad" idea ! Smile

The problem being that by doing what you describe you will end up with a negative shape and to do it nicely you would then need to do the same again reusing this shape to reproduce the original as a positive. You also need to add brackets and make it a wider to fit under the grille. Which is better done when you produce the mould for the positive shape.

That having said, as you have the luxury to have the bumper, if you go for polyester, you would be better off to either use the other side of the polyurethan if you can get it out, you would then have a near perfect positive using the inside of the skin giving you the positive shape that you need in one go without much efforts/sanding, the rough side of the polyester being on the right side.
Or if the polyurethane skin doesn't come off without a fight, you can just cut/lay some MDF or multiplex/wood and follow the guide (the bumper) to produce a negative mould giving you a positive free of sanding work in one go.

All together, for such a plate, that's much more work than recreate the shape with aluminum or flat sheets of plastics especially when you have the bumper as a guide/template. You have most measurements/angles work done for you.

73 modified Grandé 351C. Almost done. 
71 429CJ. In progress
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#10
Make it out of a piece of mild steel with two bends and miter and weld the ends and center up

[Image: 1_01_07_15_8_53_18.png]

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!
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