I need to bite the bullet and pick up an engine stand adapter for 59ab blocks. The style that I know I need is the exhaust manifold type, and there are two options that I can see: Flathead Jack's has one that slips through the upright on the stand and is welded like so: Red's Headers has a mount that appears to use studs through the plate that already exists on the engine stand: Help me decide which one would be best?
Another if you don't want to make your own is Stumpy's: http://www.stumpysfabworks.zoomshare.com/1.shtml/Ford Flathead engine stand adapters
I produced a run of them and had some limited interest. Not enough to move forward, easy to make yourself.
I have CAD drawings for the flanges from back when I was in college. I need to have a friend make one for me on his plasma CNC table. But if you have a manifold it'd be supper easy to make one. A suitably sized rectangle with the bolt holes drilled in the right spots and a correct diameter heavy wall tube cut on a 45 and welded to the plate and you're good to go.
I built mine and it is very close in looks to this one. It cost me $11 in steel bought from the local steel supply using cast off material from their remnant pile. A little time with a drill, chop saw ans welder and you have your adapter