75 to 74 bumper conversions

Acedmav75 · Nov 18, 2008

has anyone done this? i know there is a how to in the tech articles but im not sure im understanding exactly what its saying, none the less is that how its done for putting the small 74 bumper on the huge ugly 75 lol

maverick1970 · Nov 18, 2008

74 - 77 used the same size bumpers

Acedmav75 · Nov 18, 2008

hmm then what is the kind of bumper on your avatar? thats the size bumper i was talking about lol my bad putting that on my 75 that has a big bumper

maverick1970 · Nov 18, 2008

70-72 had small bumpers front and rear
73 had a slightly larger (medium) bumper on the front and small bumper in the rear with different brackets to meet the impact standards.
74-77 went to the park bench large bumpers

There were various changes with bump strips and bumper guards through the years.

Matterick · Nov 18, 2008

i have the 70-72 bumpers on my car instead of the 73.

70-72 was small(front and back)
73 bumper was midsize on the front and small still on the back(the back didn't change)
74 and up the bumper was huge front and back

Matterick · Nov 18, 2008

maverick1970 said: ↑

70-72 had small bumpers front and rear
73 had a slightly larger (medium) bumper on the front and small bumper in the rear with different brackets to meet the impact standards.
74-77 went to the park bench large bumpers

There were various changes with bump strips and bumper guards through the years.
Click to expand...

you beat me to it lol!

i always say theres plenty of room for a massive tailgaiting party on those bumpers

Acedmav75 · Nov 18, 2008

lol yea not into that i want to change it to the smaller ones lol has anyone done that kinda conversion? i know they sell the small ones in fiberglass which i want to cause itll be way lighter then those huge things lol

Acedmav75 · Nov 18, 2008

right so i just noticed you did it matterick was is hard? do you mind if you kinda take me through a walk through of how you did it like do i need to weld or make a bracket mod to fit the other one or what THANK YOU SO MUCH!

Mavaholic · Nov 18, 2008

Go here and read post #8

http://mmb.maverick.to/showthread.php?t=11033&highlight=graft

Matterick · Nov 18, 2008

heres what the post says in the thread

Mavaholic said: ↑

Here is the bumper swap article I wrote. I know its somewhere in cyber space but I couldnt find it.

First thing you need to do is gather all the parts. Its best if you have a donor car near by but you can just go to a junk yard & take measurements when you get your parts.
For the front you will need the following:
1. Bumper
2. Brackets. There are 6 brackets, 3 on each side, 2 go to the bumper, 1 goes to
the valance.
3. Stone guard. This is the panel that goes under the grill & fills the space between
the grill & bumper.
4. Valance panel
5. Valance support, center bracket. This is the bracket that bolts on the center
front of the core support. The hood latch bolts to it & it also supports the grill,
stone guard & valance panel. It is different from the 73 to 77 cars because it
extends down to support the center of the valance panel. The 73 is unique to 73
only so your donor car should be a 70 to 72 car, unless you're converting to 73
bumpers
6. Front license plate bracket (if needed)
7. Parking light / turn signals (if desired)

For the rear you will need the following:
1. Bumper
2. Brackets. 1 on each side
3. Inner trunk supports. There is 1 on each side. These pieces are welded to
the trunk floor & to the tail light panel. You must cut them out or easier yet is to
order the same part for a 67 Mustang coupe from any Mustang supply house.
They are the same.
4. Quarter extensions & small filler part at bottom of each extensions
5. Valance panel

Also get all the hardware of course
After you remove all the parts from the donor car you will need to take the following measurements. (1) The front fenders have a notch in them to allow the stone guard to come out to the ends of the bumper. 73 & up M's & C's do not have this notch. You will have to cut it out of your fenders. (2) You need to make a template of the bolt hole locations for the front bracket bolts. The front of the frame has an arrow shape to it so use that as a reference. (3) Measure for the rear bumper bracket holes or make a template. (4) Measure for the lower valance mounts. Now on to attack your car!!! Always measure 5 or 6 times before you cut metal or drill holes. I'll start on the front. Remove your bumper, filler panel, brackets, grill, the vertical support on the front center of the core support (the one that your hood latch is bolted to), & headlight doors (not necessary but don't want to ding them up). After the front is stripped down you need to fabricate a mounting system for the brackets. There are a number of ways to do this. I cut an access hole in the front of the core support to get to the inside of the frame. You have to cut out the old internal mounting bracket. It is spot welded to the inside of the frame. I used a cutting torch & sawzall. It was not an easy thing to do. If you can locate the dimples on the outside of the frame you can drill the spot welds out. I couldn't. Perhaps a better way would be to cut out the outer frame rail on the donor car. You would only have to go about 4 inches past the rear mounting hole. Then mark & cut out yours & graft in the needed section. This is the way I would go if I did it again. Another way is simply to weld the bumper brackets to the frame rail. I talked to a guy who did this. While it is much easier & faster, I don't recommend it because you will have no way to adjust the bumper once its on. That may not be a problem if done with great care, but I prefer to be able to make adjustments. Still another way is to drill through both frame rails & put a bolt all the way through with a nut on the inside. The only problem with this method is you have to take care not to over tighten the bolts because you can crush the inner and outer rails together. If you could find some steel pipe just big enough for your bolts to slide into, you could enlarge the holes in the frame rails, weld the pipe on both sides, and grind the welds flat. That would prevent crushing the rails together. I made an internal mounting bracket with a piece of 1/8" steel, approximately 2"X12". I marked the distance between the mounting holes. Then drilled the holes & welded nuts over them. Then I marked & drilled the frame for the mounting hole location. Now draw a straight line between the holes & drill 2 more smaller holes on this line. I spaced mine about 1 " from each mounting hole. Make these holes around 1/4 to 3/8". They will be used to tack weld the internal bracket to the frame rail. Now you can slide the internal mounting bracket in the frame till the nuts line up with the outer frame holes. Run the bracket bolts on them to hold them in place. Now you can spot weld the internal bracket to the outer frame rail through the 2 smaller holes. Grind your welds flush so they don't interfere with the bumper brackets. Once this is done, you can remove the bolts, & close up the front of the core support. Repeat for the other side. Once this is done, the next step is to cut the notches in the fenders. After you have marked the notches, add 1/2" to the section being cut out. You do not want to just cut out the entire notch, you need to make lips for the stone guard to bolt to. Cutting out 1/2" less will give you these edges. Just bend the last 1/2" 90 degrees to the fender surface. You will need to make a relief cut at 45 degrees between the horizontal & vertical cuts before you bend them. Study the notches on the donor car & you will see what I am talking about. Its a lot easier than it sounds. You could just change fenders too if its feasible. Once the notches & mounting brackets are done, you just bolt on all the stuff. If you use the lower lights for parking & turn signals, you need to wire them up accordingly. The grill lights can then be wired so both parking & turn signals come on at the same time with the parking lights. They are now officially sport lamps. They will need to be run through a relay or they may overload the internal circuit breaker in your light switch. Relays like these can be found at Radio shacks or some car parts stores.
Now for the back. Remove the bumper, filler strips, & quarter extensions. The bumper shock mounts need to be removed. Mine were so rusted that I couldn't get them out. I used my torch to cut them off flat to the back of the frame. Either way will work although I believe the shocks my have pressure on them so be careful if cutting them. Next, all those little holes in the tail light panel that the filler panel bolted to will have to be filled. The big ones down on the quarter panels will also need to be welded closed. These will be visible so do a good job or have a body shop do it Once all the holes are filled, the only modification is to locate the 4 bracket holes. Once drilled you can line up & weld the trunk braces to the floor & tail light panel. Careful, there's a gas tank nearby!!! You need to drill holes in the back of the quarter panels (one on each side) where the lower valance panel mounts are. Get the location from the donor car. Mount the top of the valance panel with self tapping screws. Now bolt on all the rear stuff. If you have a 74, you should have the tapered gas tank & everything will fit fine. I believe the 75 & up have the bigger squared off tanks & the bottom of the valance panel will hit the tank. All you have to do is pull out gently on the bottom of the valance, putting a bow in it, till it clears the tank. This will not even be noticeable if done carefully. Make sure you get some good self etching primer on all the bare metal to prevent rust.

Feel free to contact me if you have any questions.

Dennis
Click to expand...

newtoford · Nov 18, 2008

its a pretty easy swap. can get expensive though but it makes the car look a helluva lot better

aside from having to drill a few holes and buy a fey nets and bolts you can buy all the brackets and stuff you'll need from other cars

Matterick · Nov 18, 2008

it'll definatly be money well spent!

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75 to 74 bumper conversions

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Matterick Matt Somerville

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75 to 74 bumper conversions

Acedmav75 Member

maverick1970 MCG State Rep

Acedmav75 Member

maverick1970 MCG State Rep

Matterick Matt Somerville

Matterick Matt Somerville

Acedmav75 Member

Acedmav75 Member

Mavaholic Growing older but not up!

Matterick Matt Somerville

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