I wouldn't hesitate to tow 6k with mine as is, but I don't have any need to with a cummins/69rAisin in my fleet. That having been said, I'll be upgrading the clutch/flywheel as well whenever they do need replaced.
Seems after the 70's gas crunch the norm was straight 6 engines and high axle ratios. I had several of the late 70's early 80's trucks with the 240 or 300 and three on the tree. I remember one of my uncles trucks had the 300 six and a four speed overdrive. I don't know what the first gear...
My 70yo, 100lb, gray headed babysitter drives mine to pick the kids up from school every day, and crawls through the school pickup line with it. She's never once stalled it out, or complained about the clutch feel, or the shift points. Hmmm.
For my part, i just drive it like i stole it...
Key opening in pocket??- problem solved. Cost??- my 7yo is one round short on his rubber band gun.. told him to work on increasing his accuracy to make his fewer remaining shots more effective....
Manual sport s, stock 3.73 gears, on 35's. Hard acceleration in 1st will bark tires, aggressive shift to second at red line will bark them again. Will run 65 in second gear and still crawl well in double low.
The double overdrive would permit crazy low gears if desired, and still leave you...
You are correct, there is never any guarantee. I'm certain my hard tonneau could be popped in seconds with any type of pry tool. I simply don't leave anything under there I can't live without if I'm going to be parking at the boat ramp, or anywhere else with higher than usual break in rates, or...
Speaking to the security vs soft top issue mentioned several times in this thread, this is my one ton at a boat ramp several years ago.
Thinking ANYTHING is ever secure in a vehicle with standard glass windows is a fools errand. A thief that will cut your hard top will be equally satisfied...