Have you tried these?

http://www.sss-steel.com/shopping/ts...?sub=59&next=1

Not so quick wrote:
I'm trying to attach some wood structures to a block wall. They will have
about 50 lbs.
of weight. The blue plastic inserts pull out. The holes are 1/4". Any ideas?
I want to
avoid drilling larger holes but it's not out of the question.

Thanks
: -)