Thermostat housing / water neck recommendations?

[Rust-O-Matic]

I just picked up a new thermostat housing from O'Reilly's in yet another attempt to stop the small leak that I can't seem to get rid of. It appears to be a cast iron, stock type affair, that is proudly stamped China on the bottom.

I scraped all the old crap off the opening on the manifold, ran a file over it to make sure it's good and flat, put a VERY thin coat of permatex t-stat rtv on each side of a new Fel-pro gasket, dropped a new thermostat in, put the housing and gasket on, and finger tightened the bolts. Then i let it sit for an hour per the sealant instructions, before tightening to 25 ft lbs. I know torquing water neck bolts is a little anal, but I've had so much trouble with this damn thing I didn't want to leave anything to chance. I tightened one side half a turn, then the other side half a turn, then the other side, and so on. Before I even got to the the 25 lb setting, the housing cracked wide open. Now all the time I spent painting the neck, cleaning.the manifold, and making sure everything is just right was a complete waste.

So, my question is... now that I have to get another new neck and start over, what type would be of better quality? Would a cheap GM aluminum one be better, or are they cheap Asian made crap as well? I don't really wanna spend a fortune on anything fancy, I just want something comparable to the original quality. The old one had been on there 40 years, and been tightened so hard they stripped the threads out of the manifold (which I got the pleasure of drilling and putting in helicoils). I can't believe the new one broke so easy. I don't know if I can even take it back, because I'm sure the guy at the counter is gonna be like "uh, you tightened it too much, dummy".

Oh, and my truck is actually a '66, but the engine is a late '70s small block so I thought maybe this would be the best place to ask. Sorry for the long drawn out story, but I'm aggrivated and wanted to tell exactly what I've done in case I've overlooked something stupid. I've done this a number of times and never had this much trouble.