Re:15g on b18b
 

http://www.stealth316.com/2-3s-compflowmaps.htm

if you scroll down there is a link to a compressor map for the 15g in cfm.

it looks like the 15g will be in the middle of its efficiency at 8-12 psi on an ls, and able to handle about 18 or so psi and still be about 70% efficient. seems like a good choice in my opinion

Re:15g on b18b
 

the top wont lack as much as everyone thinks.

remember, LS only revv's to like 6800