Nairb, I am a 327 man. I love the quick and high revs so I would use that 250 hp block which is no different from the 275, 300 , 350 or 375 HP versions. Then I would go with the 327 steel crank, and try to find another one of the Dart Iron Eagle to match (trade the oddball World). I would try to use big bearings to adapt the large journal rods on the small crank journals. That will take some searching, but I think they are available. Unless you can open up the Edelbrock Torquer for a better carb, I would do some polishing on the old CI Q Jet manifold. Next would be some good headers with at least 2.5 " collectors. You did not give any specs on the Oddball head but I would hope for 62-64 cc chambers and 2.02 Intake 1.60 exhaust valves. Then you could work in some flat tops and get by with 93 octane..