Ok, here we go again. As I'm sure you've noticed by now, my Duster is a '74. I was never really a fan of the '74 bumpers, and I'd heard that they're pretty heavy. So, I picked up a 71/72 bumper to lighten things up and improve the cosmetics. So here we go with a '74 rear bumper swap.
This is my starting point. Your basic 1974 Duster bumper. Big, ugly, and with the old plastic filler that's seen better days.
So out come the tools, and off goes the bumper. I'd heard these things were heavy. Let me tell you, they're
REALLY HEAVY. Like, difficult to move by yourself heavy. Anyway, so here we are without the bumper.
See the arrow in the picture above? Well, thanks to Ma mopar not changing the tooling for the rear frame stubs, there's a hole behind that panel...
That hole is actually one of the locations for the bumper brackets on the 71/72 cars. Drill that out, and bolt up the bumper. This is where I get an "F" for my "how to", as I didn't take any pictures of the 71/72 bumper at this stage. Needless to say, I used a 71/72 style bumper with the matching brackets. I didn't use the far outer "C" brackets, as there's no bracing behind the panel there like on the 71/72 cars.
Now, the problem comes in that the old shock mount brackets go through the spot where the other hole in the 71/72 bracket is located, it goes pretty much right in the middle of that big hole the shock goes through. But, the shocks bolt to the frame about 8" back, and rather than weld a fill plate into the hole, I just made a new set of bumper brackets to bolt to the old mounting holes. I just used some 1/8" angle I had laying around.
And used that to back up the bracket on the 71/72 bumper.
No, that's not as beefy as the shock mount was. But, I suspect its fairly close to on-par with the original 71/72 mount. I could have just welded a piece of 90* angle to the frame, or just welded a patch into the lower panel, but I felt the bracket was a decent way to go. While it really isn't an issue on my car, it would be reversible as well should someone ever want to put a '74 bumper back on.
And here's the finished product! Nice, neat, tucked in bumper. And a weight savings that probably approaches 3 figures. No, seriously, not kidding. Removing the original bumper and replacing it with the earlier version actually raised my suspension in the back by almost a 1/2". The springs, which sat almost exactly at zero arch before, now have a slight arch to them.
I still have a little work to do. Notice the exhaust pipes? They were pretty much flush with the old bumper, which tells you how far that '74 bumper really sticks out! And, there's still the matter of a slight gap at the quarter. The '74 and up cars had a larger section cut out of the quarter for the bumper and that rubber filler, so a larger gap than normal is left between the bumper and quarter here.
It's just big enough for it to look "wrong", especially since the bumper fits so well everywhere else. In my case, I'm not worrying about it for now because I plan on putting a Demon tail panel on my car, and when I do I'll weld in a filler strip to take care of the gap between the quarter and new tail panel. Otherwise, a piece of weatherstripping or similar could be used to fill the gap.
So, that's it for the moment. I have my last few big ticket items on order, trying to have this thing sorted out soon so it can make some appearances at the shows and track this season.
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