I've had the 750# stand for over 20 years (I don't remember them selling the larger ones back then) and for a backyard mechanic, it's been pretty good. However, a Pontiac 350 was the largest block that it has ever supported. At a minimum go for the 1000#.
I have a 351W on the 1000# stand, call me anal but I prefer the bigger is better analogy....must get that from my wife...<whistle>
Working great and I've spun it twice....but not without help around!
i got one from Sam's club for half that money and its a good one...held my 351 w and a flathead with no problems at all, and i spun them around on the stand many times.
i think you would want to eye ball the welds in person, you do not want it falling on a toe while working with it.
heck, i think even NAPA would sell you one for that price
Watch the wheels on the cheaper engine stands. That's the weakest link, Not the stand itself. When rolling mine the wheel broke the engine fell over and crushed a carb I had sitting on the ground in a box.
I've got the 1000# version from Harbor Freight. It's got a 302 on it right now and seems pretty solid. I've got no complaints. When I bought it, they had the bigger capacity one you describe. It seemed proportionally bigger and beeifer, but I didn't need that kind of capacity.
I have the 1000# model. Had a complete 302 on it for 6 months and turned it over a few times during disassembly. If I had it to do over I would have bought the 2k model. The 1k model sags just a little with a fully dressed out engine.
I have my rebuilt 289 on a 1000# H.F. stand right now. It does sag a little since the engine is fully dressed (intake,carb,timing cover,waterpump,headers,valve covers, dist., etc.). I can't complain because it does do the job and it was cheap!
As others have said, I have a copy of their 1000# stand that is several years old now. I have had both the 460 from the Mustang and the 400 from Olds (again) hung from it. I have had no problems. The casters suck, but unless you spend a lot more for a stand, that is going to be a common problem. This stand should be just fine.