True. Which makes it that much harder to really determine just how much is too much, seeing as how I also don't have a good way of actually measuring the movement that I'm seeing either. I was actually considering mounting up my GoPro in the cab, facing the rear, to get some video of what's happening that I can later reference to measure against something like the rear glass. But then, without having accurate information on load, speed, how the suspension is moving, etc..it's all gonna be wild-butt-guesses anyways, lol.
On paper, yes. Half of the reason why I gave this truck a shot when I bought it - on paper, the HP/torque numbers are similar to what the 7.3 puts out (the other half being that I know from prior experience that I found the Chevys of this era to be FAR more comfortable inside than the Fords and Dodges). My usual haul + tow weight IS more than twice that weight too. camper weighs 3,500-4,000 pounds loaded up for a weekend, and my trailer loaded weight could be anywhere from 5,500-9,000 pounds depending on what vehicle/tools/spare parts I have loaded up (highly modified Suzuki Samura, Suzuki Grand Vitara, or Chevy K5 Blazer). Plus I'm kind of stuck with my current set up, as there aren't many toy hauler type trailers that can handle a full size vehicle well (Samurai is on full width truck axles too). Even if I switch to hillbilly hauler with the camper on a gooseneck, my trailer weight would still be about the same as my current combined, just with less of it over the rear axle of the truck.
In practice, however, it feels like the difference between running a 4.3L V6 and a 454/460 when hauling/towing, and I've seen tons of similar reports even on the Chevy specific forums - that if you intend to tow over 5K on even a semi regular basis, you want a big block gas truck or get a Ford/Dodge diesel, period. Don't even consider a 6.2/6.5 diesel truck. I figured part of that was the usual internet exaggeration, and even if it wasn't quite up to the task of hauling the camper and trailer together, it would be good enough to at least be a stand in tow rig for the car hauler alone. But I didn't think it would be this bad...
It almost feels as if the power drops off much faster past peak torque with this motor, so while peak numbers are similar, the USABLE power on the freeway is much less compared to the 7.3, but I've never found 100% bone stock dyno graphs to really compare (though admittedly, I never really tried looking all that hard either..a graph online isn't gonna suddenly make MY truck make any more power, lol).
Regardless, end story is that even if I somehow made this Chevy make more power, it isn't going to realistically be a full replacement for the Ford anyways as it just isn't going to handle the load of the camper + trailer. Sure, I could likely make some upgrades in both the drivetrain and suspension departments to get it there, but the cost of doing so would likely exceed what it would cost just to rehab my current Ford, or even buy a bigger truck instead. Hell, I even have a fresh stout 489ci big block in the Blazer now that I built last year that I could easily yank, and pop in the Chevy truck instead. But then I'm back to questioning if the rest of the truck is really going to stand up to my needs long term, and I have my doubts there too.