[BigBlockBill]

I would think a 305 from a Malibu or Malibu wagon would be almost as common as bellybuttons. I'd guess if you post here looking for one that someone would have a few they would be willing to sell.

If you do go the GT route I think a 327 350 horse L79 would be a good choice. The 350 hp was achieved at a reasonable 5800 RPM and max torque of 360 lb ft at just 3800 RPM.