I mounted mine on the HF 3 leg stand. No issues at all. Torqued all the bolts, rotated it, installed the water pump adapter... did everything with absolutely no issues.
The block total it less than 400lbs (I scrapped a 270 and it weighed in at just over 400).
I used a gantry crane to lift, then installed the back plate, then slipped it into the stand. Tool about 30 minutes.
The only thing I didn't like about the 3 leg stand is that you have to rig up a drip pan, cause the leg is in the way.
If you only have one motor to work on, the 3 leg version is fine.
In fact, here's what it looks like on this 'dangerous child killer device' (as some ppl would make you think it is)
https://www.tm9-801.com/forums/download/file.php?id=1095
