I would suggest finding a cheap honda or as CDOWNS suggests a geo. For commuting a little econobox will triple or quadruple your MPGs. I bought my wife a Honda Fit. It gets 45+ mpg, less smog...and since its not a hybrid it doesn't produce any SMUG!
A big block is a sweet power plant but by no means a commuter in todays market but that's why you posted isn't it?!?
I feel ya tho. I used to commute 110 miles round trip in my CJ5 with the 304. Half a tank easy. Super fun but totally impractical. now it's a restored rock hound.
As far as others commenting on oil being around for awhile... if it was plentiful they wouldn't be screwing us with ethanol blends. "Peak Oil" is happening... if it wasn't so scarce the gulf wouldn't be dying a slow death and we wouldn't be taking control of all those middle east oil fields.
IMHO