valve covers that won't leak - ??

The first ones were OEM on tons of GM products.
Never needed or used the bars, but I can see that they could help distribute the load a bit more.

My neighbor was bitching over there across the street one day and I asked him what was up, and he said his 3rd set of cover gaskets were leaking.
I walked over and saw all the bolts tightened down so far that the covers were bent and gasket material squeezed out the sides and split around every bolt.
Uh, there's your problem. :D

It didn't help that they were super cheapie chrome aftermarket and thin as paper almost.