the stock lowers are pretty good, its the gasket and bolts that have an issue:

http://www.supersixmotorsports.com/pdf/40SOHCTech.pdf

 

"The high 9.7:1 stock compression ratio and deck integrity of the cylinder heads will probably lead to head gasket retention problems in power adder applications"
and
"Supercharged setups really need to reduce the compression ratio from 9.7:1 to 9.0:1"

9.7:1 is high?

hmmm. interesting read but i don't remember anyone complaining about these things. not that i am calling super six liars but take JimC for example. 150k miles, blown, stock internals and no problems so far

 

the article was published in 2005 and I did find some issues with some of their findings but mostly spot on. A lot of guys have been going 7-11# with no problems. Just a little more info that may help.

 

hm. Well, I think I'll shoot for 10lbs and a good dual exhaust kit for now and that should hold me over until I can get my twin turbo LS1 swap in