318 and boost...

The short answer is YES.
Low Compression (anything under 9.5:1) will stand upto 20ish PSI...with NO Modifications to a Stock Longblock....above 20 psi, a set of MLS (multi layer steel) head gaskets and ARP HeadStuds and the longblock can go as far as you can supply the fuel for.

Like you said, 318's are practically FREE....its worth the venture if the financials can support it.

I know of more than (3) single turbocharged 88-93 5.0L Mustangs over 600hp on stock internals....that drive to the track and rip 10's (one mid 9's) street legal on Drag Radials.

If a 5.0L Turd Block can stand it....why cant a SBM?

Here's a single turbo dart 318 on youtube:
[ame="http://youtu.be/B74ACQbowas"]302 Found[/ame]