The big issue with enhanced after market bumpers isn't the bumper itself. All I've seen are superior to the factory bumper and most retain the rear cross member of the frame (I know a few designs clip out that x-member to gain a degree or two more of departure angle, but they seem to be as strong as it is or better with what they replace it with), which provides a pretty robust layer protection underneath it all. More on this in a moment.
The main issue is whatever is mounted to the bumper: tires, cans, etc on the swingouts. The bumper will probably be fine, but if the offending vehicle is high enough to push into them, it usually results in substantial damage to the rear hatch/tailgate area. And almost all aftermarket bumpers hang the swingout cargo in a way that projects backward past the plane of protection offered by the bumper they're mounted to. There is really no avoiding this problem without intruding on other areas, like departure angle, the weight of the bumper, etc. Swingouts are a very handy feature for a lot of reasons, but maybe a good idea to make provisions for in your insurance for extra equipment just so if the worst comes to pass and you get hit, your insurance adjuster has documentation it won't be a cheap fix. Of course, with older vehicles, it's vexing to maintain anything but what is basically auction value insurance.
I've not had the bad luck to be rearended in an 80. My FJ55 did take a substantial hit, with relatively little damage. My neck has never been the same. The design is essentially the same as the 80 and I suspect the 80 is even stronger. The rear x-member forms the inner part of the rear bumper, with a cosmetic overlay.
I was stopped at a light just past an underpass. The fellow who hit me had just got off work and was either daydreaming or perhaps had some sun in his eyes. The screech of the tires hopelessly clawing the road drew my attention and I just turned my head to see what was up in the rearview -
BAM! - smacked his AMC suckwagon square into me, probably at 25 to 30 mph. It totaled his car, as the bumper went right under the 55's, shearing everything in the engine compartment off above that. The 55 basically had a few scratches in the middle part of the bumper. The bumper ends were somewhat mangled as you can see in the pic, but did their job of mostly protecting the lower corner of the body on each side. It amounted to about $500 damage in 1980 dollars. I didn't discover until later that it bent the bench seat mounts. My '76 55 didn't have headrests, apparently being among the last made without them, although it did have the mounts for them under the vinyl of the seat cover.
The set-up on the 80 is quite similar. Not much to worry about there, except your neck
, unless someone bigger or faster hits you. Consider the utility of swingouts versus their status as blunt objects if you're worried about a rearender. I know I do, but it's more because my neck can't take another one of these; the truck will be OK.
