Rear bumper difference 73-80 vs 81–

[Retoxtony]

I was wondering if anyone can tell me what the actual difference is between bumpers on a 73-80 vs 81 forward. My truck is a 79 but the previous owner mounted a 81 and newer bumper on it. The bumper is in rough shape so I was going to order a new one but I’m don’t know if my mounts will line up if I order the proper one for my year of truck.

 

[JBswth]

The brackets for the front are different. If he didn't modify the frame horns, factory-style mounts for your style are what you need. If he did though, then, if memory is correct, you will need two of your stock front brackets per side, (the ones that bolt to the front of the frame horns), and do some drilling. Mount the outer brackets to the frame and bumper and support the bumper, get it perfectly straight and level, then figure out where the brackets that go to the front of the frame horns should go, mark where you want to drill. If the stock hole for the upper bracket is still present, it makes it that much easier. You just have to drill for the lower ones.

 

[Redfish]

Are you asking about the front or the rear? I agree with @JBswth about the front being different but I don't know that there is a difference in the rear bumpers. I think there was more variation from different brands of aftermarket bumpers than there was between the different years.

 

[Retoxtony]

Rear bumpers.

I keep coming across conflicting info on if I’ll need to buy new brackets or not. I’m not even 100% sure what bumper is on my truck now. I know for sure it’s not a 73-80, but it has the impact strips so a few people have told me it’s a blazer or suburban bumper not a truck bumper.

 

[mtbadbob]

I believe the only difference is whether the bumper has corner supports, or the type that are in line with the frame. If I'm not mistaken, both types bolt to the outer side of the frame. The bolt patterns on the frame might be different, but one can always drill new holes either in the brackets, or frame. I just changed from a corner support rear bumper, to the straight to frame mounts on my '87, and the bolt holes lined up. There are 4 on each frame rail.

 

[mtbadbob]

Crawl under your truck & snap some pictures of the brackets how it mounts to the frame & bumper itself. Look to see if there are visible bumper bolts toward the corner of the bumper, or if they are concealed. It's possible the other owner drilled different holes in your frame also. Google & YouTube are your friends!

 

[Redfish]

It sounds like we are discussing different styles rather than different years. The "step" rear bumper that came on these trucks should be the same from '73 to '87. A lot of folks switch to the rounded bumper of the Blazer/Jimmy style which has no place to mount a trailer ball. The different styles do in fact require different mounting hardware. Every reputable place that I know of offers the mounting kits for the different bumper styles. You could probably get a good parts breakdown on the LMC Truck website even if you choose not to buy from there. Brother's Truck, USA 1 Industries and a few others offer both types of bumper and the mounting kits.

The 1973 to 1987 TRUCK bumper, a "step" style bumper looks like this:

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The Blazer/Jimmy style looks like this:

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[75gmck25]

In that timeframe the rear bumper was an option. It was common for a truck to come in with none, and then the dealer installed whatever type you wanted.

 

[AyWoSch Motors]

The frame horns are all the same, but the bracket that bolts to that is different depending on the bumper.
On the front, youd have to change out all 4 of the brackets.
On the back, box bumpers are universal fit from 73 to 87. If your taking sport bumper, its the same story as the front, there 4 different brackets of different shoes depending on the year.

I had a box bumper on my 86, and I changed it out for an 80s style blazer/suburban/sport bumper. I used the outer bu per brackets from my 75 blazer. The bolt holes lined up the same, but the contour was different. I ended up smashing down the bottom with a mallet, and putting in a stack of washers as a spacer for the top. The inner 2 brackets I used the old bolt on part from the old box bumper, and welded up some new brackets to match the shape perfectly.
Looks factory. Then I welded up my own reese hitch for underneath that.
I got some pics somewhere....

 

[Retoxtony]

You can see in the first pic the bumper i currently have. This is not the original bumper the truck came with, it was put on by one of the previous owners. I like the way it looks but the chrome is pitted very bad and its scratched up pretty bad from use. I'm almost positive its a 81 and newer style bumper and the previous owner modified the mounts to make it fit. So if thats the case it would be easiest to get one for the same year as the bolt holes should match right up. I'm just not sure how much difference there actually is for the proper bumper because i dont have one.

 

[AyWoSch Motors]

You can see in the first pic the bumper i currently have. This is not the original bumper the truck came with, it was put on by one of the previous owners. I like the way it looks but the chrome is pitted very bad and its scratched up pretty bad from use. I'm almost positive its a 81 and newer style bumper and the previous owner modified the mounts to make it fit. So if thats the case it would be easiest to get one for the same year as the bolt holes should match right up. I'm just not sure how much difference there actually is for the proper bumper because i dont have one.

Ah, that's a 88-91 suburban bumper.
With what you have set up there, you should be able to swap to a 73-80 sport bumper on there without much issue. The outer bracket you have is homemade, and will transfer easily. The center bracket looks like a factory 81-87 (88-91) bracket modified to bolt on. The bolt holes on that will line up the same, although you may need to add some washers behind it. I'd say that's completely doable without having to modify anything or spend much.
If the center ones dont sit well, you could take what you have there and modify it, or make a custom one like I made. Very easy.

 

[Termite_Delight]

So this is what you are looking for...

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[AyWoSch Motors]

So this is what you are looking for...

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Thatd be exactly what hed need to do the swap properly.

 

[Retoxtony]

Thanks guys. I’ll be honest and say I don’t think I’ll be doing it “properly“. I’ll probably order a bumper and make it work with the existing brackets. Maybe modify things a bit if I have to. I’m going to try to order the proper bumper for a 79 but if it’s out of stock I’ll probably get the newer style If that’s in stock.

 

[AyWoSch Motors]

Thanks guys. I’ll be honest and say I don’t think I’ll be doing it “properly“. I’ll probably order a bumper and make it work with the existing brackets. Maybe modify things a bit if I have to. I’m going to try to order the proper bumper for a 79 but if it’s out of stock I’ll probably get the newer style If that’s in stock.

You should be able to put a 79 on with what you have there, relitivly easily.