Yea, crushing the fender on the '55 was a rather painful lesson. Same with the short-tongued 24' enclosed car trailer.
You guys are wise to question the cheap-chinese stuff that many of us insist on purchasing from Harbor Fright, um, I mean Harbor
Freight 
Having said that, I've personally used two HF tow bars as a bases from which to build from for 3 different set ups. The HF 5k lbs one is the same as the (re-boxed) ones that U-Haul sells their customers, I've had both in my own hands, looking at them side-by-side. The caution is with that kind of adapting, you just have to 'overbuild', load test it yourself, then inspect for cracks and bends often. This is smart for towing no matter where the steel and parts were made. Words to live/tow by: Me running my rig off the road hurts only me and my passengers. Me loosing my trailer, it crossing the centerline into some innocent family on their way to church is totally inexcusable and damned criminal.
Remember that extending the hitch creates a cantilever-effect that stresses the hitch and the hitch attachment points, in ways the engineers at Reese, Draw-tite (or whomever) never thought of. From experience, I'd extend the tow bar itself, before extending the hitch, if at all possible. If you must extend the hitch, give Reece a call and talk to an applications engineer, those guys do
real engineering on their products. With HF you often get a copy of a copy with some cut-corners for manufacturing cost reduction.
I once extended the hitch on my F350 dually, Lance 11-1/2' cabover rig, so I could safely tow that 24' enclosed race trailer of mine, including the added stress of employing a weight distributing hitch. With that kind of load, I wanted an engineered solution, which was not easy or inexpensive, extended it 38" I think it was. I looked at several possibilities, but wound up buying a brand new hitch made specifically for that purpose from Reece and sold only through Lance dealers at the time. Not that I think you need this for flat towing for FJ40, but that impressive hitch was built around a 2-1/2" square inside receiver tube extension (instead of the normal 2") and 42" long! Talk about hitch-envy, hahaha! Granted, my trailer had a lot of tongue weight to cantilever off the truck, but Reece really did their homework to come up with a safe solution for the cabover camper guys who wanted to tow 7500lb horse or race trailer with 500lbs of tongue weight. I still have the hitch, it's massive, like a normal class III on steroids, everything is bigger, thicker and stronger, more frame attachments spread out over more frame rail with huge bolts. I towed with that hitch/trailer/camper rig for several years, maybe 20k miles, to and from racetracks.
http://www.etrailer.com/Trailer-Hitch/D ... 45293.html
http://www.etrailer.com/Hitch-Accessori ... 45292.html
Sportsmobile (AKA Money Pit)
Linear Mode
