block filler

[LGMCAFEE@aol.com]

 Has any body used the concrete type filler that they put in blocks to make 
them more rigid. I know they use this a lot in drag racing but will this work 
for the salt. I am going to bore a 283 out to 302 and thought I might fill 
the block about 1/2 full.
If I do go this route should I fill before having it bored?
Thanks Larry Mac