There was a terrific article on racing with the Ecotec in 'Race Car Engineering,' subtitled something like '1000bhp off the shelf.' I think the beginning of the year. I'm having no luck digging it out right now.
They suggested that there's already whatever upgrade you want available OEM for your existing block, but of course it's going to cost you. Still, literally, they made it sound like you could yank it out of your Cobalt and put it back together as you want it.
That engine is all over the place, like the SoCal Speedshop Ecotec Lakester. Definitely living up to some potential.http://www.gm.com/automotive/gmpowertra ... /index.htmhttp://www.ecotecpower.com/
Lingenfelter was putting out 1000 whp with them no problems.
As far as the block, you shouldn't be able to destroy it in this kind of an application. It's basically 1/2 an LS1. 6 bolt main, deep skirt block.