Well being exactly to spec and causing a catastophic failure are two different things.
Everything is relative. Look at the 5/16" bolts they use in 302 Ford motors. There's more clamping force on a Slant-6 carb than one of those and they survive with superchargers (some of them anyway)
The question was is rod work necessary and I think it is. New bolts and resizing the big end for a normal street car should be adequate. I rebuilt plenty of motors back in the day (mostly big blocks) and did neither, but I sure don't recommend it. 
Certainly catastrophic failure is not an option. I want to feel confident that I am not going to blow anything if I spin it to 6,500 or 7,000. And I don't really want an engine that sounds loose or rattly due to excessive clearances. I do have to keep in mind that this is a street machine, though, and like most, I have a budget to try and work to (already blown out). I would imagine if I left the big end alone and just changed bolts, I could end up with inconsistent cleanances between rod journals possibly resulting in noise, lower oil pressure, or spun bearing. So I it is probably worth the extra $120 to size that end.
How much clearance is acceptable on the small end for full floating rods? And, although I don't know how hard it was run, with only 74,000 miles on the engine how likely is it that they would need work due to bushing wear?
